- Preheat your oven to 350°F.
- Grease and flour two 9-inch round cake pans.
- Beat the egg whites until stiff, and set aside.
- In a large bowl, cream together the butter, oil, lemon extract, and sugar for 3-4 minutes or until light and fluffy.
- Stir in the egg yolks individually, then the vanilla; combine them thoroughly.
- In a separate bowl, mix the flour, baking soda, and baking powder. Alternate adding the buttermilk and dry ingredients to the wet ingredients.
- Mix until just combined, and then fold in the egg whites.
- Pour the mix evenly into the prepared pans. Bake them until a toothpick inserted comes out clean, 20-25 minutes.
- Remove the pans from the oven, and allow them to cool for 15 minutes. Then, turn the cakes out onto cooling racks, and let them cool completely.
- In a medium-sized bowl, combine the cream cheese, butter, vanilla and powdered sugar, and beat until light and fluffy.
- Spread the first cake layer with frosting, and top it with blueberries.
- Repeat Step 1 three times, creating a three-layer cake. Arrange more blueberries around the edge of each layer for structure.
- Top the cake with more blueberries, and refrigerate for at least 1 hour.
- Slice, serve, and enjoy your Birthday Cake!
Remember to remove candles before eating!