Step 1

Preheat oven to 350 F. Grease (9-inch round baking pans with shortening and lightly coat with flour. Set aside. (I used dark, non-stick pans)

Step 2

In a large bowl, sift together flour, baking powder, and salt. Set aside.

Step 3

In another large bowl, cream together butter, shortening, and granulated sugar until well combined.

Step 4

Mix in eggs and egg yolks one at a time. Then mix in vanilla extract and lemon extract. Set aside.

Step 5

In a medium-sized bowl, stir together sour cream, milk, lemon zest, and lemon juice until combined.

Step 6

Mix the dry ingredients into the creamed sugar mixture, while alternating with the milk mixture. Mix until batter is fully combined and no flour remains. The batter will be thick and fluffy. Set aside.

Step 7

In a medium-sized bowl, add blueberries and flour. Gently toss so that blueberries are coated into the flour. Pour blueberries into the batter (including any remaining flour from the bowl)

Step 8

Very gently fold the blueberries into the batter, being careful not to break them open.

Step 9

Pour the batter evenly into the 3 prepared pans.

Step 10

Bake on the middle rack for 24-26 minutes (check on it at the 20-minute mark.) or until a toothpick inserted into the center comes out clean.

Step 11

Remove cake from oven and when the pan is cool enough to touch,( run a knife along the inside rim of the pans if needed) and gently turn the cakes out onto a cooling rack to finish cooling completely.

Step 12

When the cakes are almost done cooling, make the frosting by creaming together butter and cream cheese until well combined.

Step 13

Add in vanilla extract.

Step 14

Mix in powdered sugar a cup at a time, until frosting becomes creamy.

Step 15

Frost, stack, and decorate the cake!

Step 16

Refrigerate the cake to let the frosting firm up to create smooth frosting lines. Store cake in the fridge and allow to come to room temperature before serving.