Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans with unsalted butter and dust with flour.

Whisk together the all-purpose flour, baking powder, baking soda, and salt until well combined in a medium bowl.

Cream the softened butter and granulated sugar together in a large mixing bowl until light and fluffy, about 4-5 minutes.

Add the eggs and extra egg yolk one at a time, mixing thoroughly after each addition.

Stir in the lemon zest, lemon juice, vanilla extract, and almond extract (if using), mixing on low speed until blended.

Gradually add the flour mixture and buttermilk alternately, starting with the flour and mixing until just combined.

Gently fold in the fresh blueberries, ensuring they are coated with a little flour.

Divide the batter evenly between prepared pans and smooth the tops. Bake for 25-30 minutes until cakes are golden brown.

Remove cakes from the oven, let cool in pans for 10 minutes, then turn out onto wire racks to cool completely.

While the cakes cool, beat together the softened butter and cream cheese until light and fluffy. Gradually add powdered sugar, mixing well.

Stir in vanilla extract and lemon juice until frosting reaches desired texture.

Once cooled, place one cake layer on a serving plate, spread frosting on top, add second layer, and frost top and sides as desired.