Flag Cake is the recipe that Lucia makes every Fourth of July and every Memorial Day and every patriotic summer gathering where she needs a dessert that feeds twenty-four people effortlessly, looks completely festive and genuinely beautiful, and tastes so much more extraordinary than a basic boxed cake that every person at the party assumes she made everything from scratch. The secret is in how the box cake mix is prepared. Rather than following the box instructions, she combines the mix with eggs, sour cream, cold milk, and melted butter in a method that produces the most tender and deeply flavorful cake that genuinely tastes like a bakery-quality vanilla layer cake rather than anything that came from a box.
The vanilla pudding and Cool Whip topping is light and airy and not overly sweet. And then the blueberries in the corner and the rows of sliced strawberries across the top make every square of this cake look like the most completely charming and completely American patriotic dessert imaginable.
Flag Cake is the most festive and easy patriotic Fourth of July sheet cake made with a bakery-enhanced white box cake mix and a light vanilla pudding and Cool Whip topping decorated with fresh blueberries marshmallows and sliced strawberries arranged in the most beautiful American flag pattern for the most completely celebratory and crowd-pleasing summer dessert. Come follow us on Pinterest where we share beautiful patriotic dessert recipes and easy summer celebration baking favorites from our kitchen every single week.
Table of Contents
Why You Will Love This Flag Cake Recipe
This Flag Cake recipe is the patriotic summer dessert that solves every Fourth of July and Memorial Day dessert challenge because it feeds twenty-four people from a single pan, requires minimal active preparation time, can be made almost entirely the day before the party, and produces a result so visually striking and deeply festive that it immediately becomes the most photographed item at every gathering it appears at.
The sour cream, melted butter, and cold milk method for preparing the boxed cake mix is the technique that transforms a conventional box cake into the most completely extraordinary and genuinely bakery-quality vanilla sheet cake. The sour cream adds fat and mild acidity for the most tender and moist crumb. The melted butter adds rich dairy flavor. The cold milk produces the most even batter consistency. Together these simple additions make the finished cake taste completely different from any standard box mix result. Our Soft Vanilla Cake makes a beautifully from-scratch and equally crowd-pleasing companion for a complete and wonderful summer celebration cake collection.
Ingredients Needed for This Flag Cake Recipe
For the Cake:
- 1 box (15.25 oz) White or Vanilla Cake Mix
- 3 large Eggs, room temperature
- ½ cup Full-Fat Sour Cream, room temperature
- 1 cup Cold Whole Milk
- ½ cup (1 stick) Unsalted Butter, melted
For the Vanilla Whipped Topping:
- 2 cups Cold Whole Milk
- 1 box (3.4 oz) Instant Vanilla Pudding Mix
- 1 container (8 oz) Whipped Topping (Cool Whip), thawed
For Decorating:
- Fresh Blueberries
- Sliced Fresh Strawberries
- Mini Marshmallows (optional, for stars)
- Unsweetened Shredded Coconut (optional, for white stripes)
How to Make This Flag Cake Recipe
In a large mixing bowl, stir together the cake mix, room-temperature eggs, room-temperature sour cream, cold milk, and melted butter until smooth and evenly combined. For the most evenly incorporated batter, make sure the eggs and sour cream are at room temperature before beginning as this prevents lumping and produces the most evenly textured finished cake.
Transfer the batter to a greased 9 by 13-inch baking pan and spread evenly with a spatula. Bake according to the temperature and time instructions on the cake mix box. When done, place on a wire rack to cool completely before adding the topping. Allow a full 30 to 45 minutes for complete cooling, cara mia. A warm cake will melt the whipped topping immediately on contact.
For the vanilla whipped topping, whisk the cold milk with the instant vanilla pudding mix for approximately 2 minutes using a whisk, fork, or electric mixer on medium speed until the pudding has thickened. Use a rubber spatula to stir the vanilla pudding together with the thawed Cool Whip until completely combined and uniformly smooth. Spread this light and airy vanilla whipped topping evenly across the entire surface of the completely cooled cake using an offset spatula.
To decorate the flag pattern, outline a square in the upper left corner of the cake with a row of blueberries. Fill in the square with remaining blueberries, leaving small white spaces between them to represent stars. Fill those white spaces with mini marshmallows if desired for a more dramatically star-filled corner.
Line sliced strawberries in 4 to 5 horizontal rows across the right two thirds of the cake surface to create the red stripes of the flag. In between each row of strawberries, leave a stripe of white whipped topping visible or fill in with a row of shredded coconut for white stripes. Refrigerate for at least 1 to 2 hours before serving for the most beautifully chilled and completely refreshing flag cake.
How to Serve This Flag Cake Recipe
Serve cold directly from the refrigerator for the most completely refreshing and delicious summer flag cake experience. The cool and airy vanilla pudding topping against the moist and tender vanilla cake base with the fresh cold berries is genuinely extraordinary on a warm summer day.
Slice into 24 portions directly from the pan for the most effortless crowd-serving experience. No plating assembly required. For a party, serve straight from a cooler filled with ice for the most convenient and food-safe outdoor serving experience. Our Strawberry Shortcake Sheet Cake makes a beautifully equally crowd-pleasing and equally strawberry-vibrant companion for a complete and wonderful summer celebration dessert spread.
How to Store This Flag Cake Recipe
Store covered tightly in the refrigerator for 3 to 5 days. Push toothpicks gently into the surface before covering with plastic wrap to prevent the wrap from disturbing the berry decoration. For make-ahead preparation, bake the cake the night before and refrigerate tightly covered. Make the whipped topping and refrigerate separately. Decorate with berries on the day of serving for the most fresh and beautiful result.
Tips to Make This Flag Cake Recipe
Make the cake the night before for the most completely stress-free party day preparation. Overnight refrigeration actually improves the cake’s moisture and flavor as the sour cream and butter have time to fully integrate through the crumb. The day-of preparation then requires only the topping application and the fruit decoration.
Use the freshest and most vibrant berries available for the most beautiful flag decoration. Wash and dry the berries several hours in advance and refrigerate them until needed for the most beautifully crisp and food-safe berries for decorating.
Helpful Notes for This Flag Cake Recipe
Instant vanilla pudding mix rather than cook-and-serve is specified in this recipe. Cook-and-serve pudding does not set to the correct consistency when simply whisked with cold milk and does not produce the stable and spreadable whipped topping that the recipe requires.
The shredded coconut for the white stripes is optional but adds a beautifully textured and slightly sweet element that makes the stripes more visually defined and more completely beautiful from a distance. Unsweetened shredded coconut is specified to keep the overall sweetness of the topping balanced and pleasant.
Variation of This Flag Cake Recipe
Maria made a version using rows of fresh raspberries in place of the strawberries for a flag cake with a more intensely tart and vibrant red stripe that was completely extraordinary and deeply patriotic. Teresa tried using fresh pineapple chunks arranged decoratively across the top of the whipped topping rather than following the flag pattern for the most beautiful and completely tropical summer sheet cake that was deeply vibrant.
For a completely homemade version, substitute a full homemade vanilla cake batter in a 9 by 13-inch pan in place of the box mix for the most completely from-scratch flag cake that is deeply satisfying for those who prefer baking without packaged mixes. Our Vanilla Cake makes a beautifully completely homemade and equally crowd-pleasing companion for a complete and wonderful summer celebration cake collection.
FAQs About This Flag Cake Recipe
Why use sour cream and butter with the box cake mix?
Using sour cream and melted butter with the box mix in place of the standard oil and water produces a significantly more moist, more flavorful, and more tender cake that tastes genuinely bakery-quality rather than boxed. The sour cream adds fat and mild acidity that tenderizes the crumb and the butter adds a deeply satisfying dairy flavor that oil cannot replicate.
Can I make this flag cake without Cool Whip?
Yes. Whip 2 cups of cold heavy whipping cream with 2 tablespoons of powdered sugar and 1 teaspoon of vanilla to stiff peaks for a completely homemade whipped cream topping. Combine with the prepared vanilla pudding in the same proportions as the Cool Whip version. The homemade version has a richer and more dairy-forward flavor.
How far in advance can I decorate the cake?
Add the blueberries and strawberry decorations no earlier than a few hours before serving for the most vibrant and beautiful berry appearance. Berries added too far in advance can release juice that bleeds into the white whipped topping and makes the flag decoration appear less crisp and defined.
Conclusion
This Flag Cake is the most completely festive and genuinely beautiful patriotic summer dessert that makes every Fourth of July and every Memorial Day table feel the most completely celebratory and deeply American through the most cheerful red white and blue berry decoration and the most completely refreshing and crowd-pleasing combination of moist vanilla cake and airy vanilla pudding topping in every single cold and beautiful slice. We hope it brings the same deeply patriotic summer joy and the same completely satisfied crowd to your kitchen that it has always brought to ours. Make it, share it, and come back to tell us all about it. With all our love, Maria, Lucia, and Teresa
Print
Flag Cake The Most Easy and Festive Patriotic 4th of July Sheet Cake You Will Make
- Total Time: 50 minutes plus chilling
- Yield: 24 slices 1x
- Diet: Vegetarian
Description
The most festive and easy Flag Cake made with a white box cake mix enhanced with room temperature eggs sour cream cold milk and melted butter for a bakery-quality vanilla sheet cake baked in a 9×13-inch pan topped with a light vanilla pudding Cool Whip topping and decorated with fresh blueberries in the upper left corner and rows of sliced strawberries to create an American flag pattern serving 24 people. A completely spectacular and crowd-pleasing patriotic 4th of July dessert.
Ingredients
1 box 15.25 oz White or Vanilla Cake Mix
3 large Eggs room temperature
1/2 cup Full-Fat Sour Cream room temperature
1 cup Cold Whole Milk
1/2 cup Unsalted Butter melted
2 cups Cold Whole Milk for topping
1 box 3.4 oz Instant Vanilla Pudding Mix
1 container 8 oz Cool Whip Whipped Topping thawed
Fresh Blueberries
Sliced Fresh Strawberries
Mini Marshmallows optional
Unsweetened Shredded Coconut optional
Instructions
1. Stir cake mix, room temperature eggs, room temperature sour cream, cold milk, and melted butter until smooth.
2. Transfer to greased 9×13-inch pan. Spread evenly.
3. Bake according to cake mix box temperature and time instructions.
4. Cool completely on wire rack 30 to 45 minutes.
5. Whisk cold milk with instant vanilla pudding mix 2 minutes until thickened.
6. Stir pudding and thawed Cool Whip together until smooth.
7. Spread vanilla whipped topping evenly across completely cooled cake.
8. Outline square in upper left corner with blueberries. Fill in with more blueberries leaving white star spaces.
9. Fill star spaces with mini marshmallows if desired.
10. Arrange strawberry slices in 4 to 5 horizontal rows for red stripes.
11. Fill between strawberry rows with shredded coconut for white stripes or leave white.
12. Refrigerate at least 1 to 2 hours before serving. Serve cold.
- Prep Time: 20 minutes
- Cook Time: 30 minutes
- Category: Dessert, Cake, Patriotic
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 slice
- Calories: 107
- Sugar: 6g
- Sodium: 127mg
- Fat: 7g
- Saturated Fat: 4g
- Unsaturated Fat: 2g
- Trans Fat: 0g
- Carbohydrates: 9g
- Fiber: 1g
- Protein: 3g
- Cholesterol: 52mg
Keywords: flag cake, 4th of July flag cake recipe, patriotic sheet cake strawberries blueberries, easy American flag cake for Fourth of July
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