Step 1

Combine flour, sugar, baking powder, baking soda and salt in a large bowl and whisk together.

Step 2

2.Add eggs, oil and lemon juice. Beat until smooth.

Step 3

Add sour cream and beat until smooth.

Step 4

Bake at 350 degrees in two 8-inch pans for about 25 minutes or until done.

Step 5

Combine all ingredients in a double boiler (or in a metal bowl over a pot of simmering water, like I did).

Step 6

Heat while stirring constantly with a whisk.

Step 7

It is done when it’s thick enough to coat the back of a spoon. You will be able to tell it has thickened, but I wouldn’t say that it’s “thick.”

Step 8

Refrigerate until cool and thick.

Step 9

Beat butter and shortening together until smooth.

Step 10

Add 6 cups of powdered sugar, one at a time, beating to combine.

Step 11

Add lemon juice, lemon zest and vanilla and combine.

Step 12

Add the remaining powdered sugar and beat to combine.

Step 13

Add water to get the consistency you want, starting with 1/2 tsp, beat to combine.

Step 14

Divide the cake into four layers by slicing each cake in half.

Step 15

Fill two layers with lemon buttercream and the other two with lemon curd.

Step 16

Frost the outside of the cake.