The most extraordinary bright Lemon Cookie Cake made by preheating oven to 350°F greasing 12-inch round pan or 9-inch round pan with parchment whisking 2 1/2 cups flour 1 tsp baking powder and 1/4 tsp salt beating 1 cup softened butter and 1 cup sugar medium-high 2 to 3 minutes light and fluffy adding 1 room temperature egg 2 tsp fresh lemon zest 2 tbsp fresh lemon juice and 1 tsp vanilla mixing well mixture may appear slightly curdled this is normal adding flour mixture on low just until soft dough forms pressing evenly into pan with dampened hands baking 16 to 20 minutes until edges lightly golden and set and center slightly soft cooling completely beating 8 oz room temperature cream cheese and 1/4 cup room temperature butter smooth adding 2 1/2 to 3 cups sifted powdered sugar 2 tbsp lemon juice 1 tsp lemon zest and optional yellow coloring beating fluffy spreading over cooled cookie cake whisking 1/2 cup sifted powdered sugar with 1 to 2 tbsp lemon juice to glaze drizzling decoratively and scattering additional lemon zest. A completely perfect bright spring lemon cream cheese frosting glaze giant cookie cake recipe.