Prepare the Blackberry Puree: In a medium saucepan, combine fresh blackberries, sugar, and a splash of water. Cook over medium heat for about 10 minutes until thickened, then strain, and cool completely.

Preheat the Oven and Prepare Pans: Preheat your oven to 350°F (175°C) and prepare your cake pans by greasing and lining with parchment paper.

Mix Dry Ingredients: In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly blended.

Cream the Butter and Sugar: In a stand mixer, cream together the unsalted butter and sugar for about 3-4 minutes until light and fluffy.

Add the Eggs and Flavorings: Add the eggs one at a time, mixing well after each. Add vanilla extract and lemon zest, mixing until smooth.

Combine Wet and Dry Ingredients: Alternately add the flour mixture and cooled blackberry puree to the creamed mixture until just combined.

Bake the Cake Layers: Divide the batter between the prepared pans and bake for 28-32 minutes or until a toothpick comes out clean.

Cool the Cakes: Allow the cake layers to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

Make the Creamy Frosting: Beat together cream cheese and unsalted butter until smooth, then gradually add powdered sugar and blackberry puree.

Frost and Decorate the Cake: Once the cake layers are cool, frost between the layers and on the top and sides of the cake.