1. Preheat oven to 350°F. Grease two 6 or 7 inch cake pans, dust with flour, and line bases with parchment.

2. Whisk milk and apple cider vinegar together and rest 5 minutes to make homemade buttermilk.

3. Pulse pistachios and sugar in a food processor until finely ground with a little texture remaining.

4. Whisk pistachio sugar mixture with flour, baking powder, and salt in a medium bowl.

5. Whisk buttermilk, olive oil, vanilla, and almond extract together in a large bowl. Add green food dye if using.

6. Fold dry ingredients into wet ingredients until just combined. Do not overmix.

7. Divide batter evenly between prepared pans and bake 25 to 30 minutes until a toothpick comes out clean.

8. Cool completely then wrap and refrigerate overnight.

9. Beat salted butter and blackberry preserves until smooth.

10. Add powdered sugar gradually on low speed until combined.

11. Add vanilla, salt, and dried thyme then beat on medium 4 to 5 minutes until light and fluffy.

12. Level one cake layer if needed and place cut side up on cake stand.

13. Spread buttercream and spoon blackberry preserves in the center.

14. Place second layer on top and frost with remaining buttercream.

15. Garnish with fresh blackberries and chopped pistachios. Rest 30 minutes at room temperature before serving.