1. Grease and flour two 8-inch cake pans.  Preheat oven to 350 degrees.

Cake

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

2. Add eggs, oil and lemon juice and mix until smooth.  Add sour cream and mix until smooth and cream.  Pour batter evenly into cake pans.

3. Bake at 350 degrees for about 25 minutes, or until center springs back when touched. Remove to a wire rack to cool for 10 minutes.  Remove from pans and allow to completely cool on wire rack.

4. Divide cake into four layers by splitting each cake in half horizontally.

Lemon Buttercream

1. With a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until creamy – about 2 minutes. Add confectioners’ sugar, lemon juice, heavy cream, and zest with the mixer running on low. Increase to high speed and beat for 3 full minutes. Taste and add salt if needed. Add up to 1/2 cup more confectioners’ sugar if frosting is too thin or another Tablespoon of cream if frosting is too thick.

Assembling the Cake

1. Place first cake layer on serving plate.  Pipe a ring of buttercream around the out edge to hold in the lemon curd.  Spoon half of the curd into the center of the buttercream ring and spread evenly.  Place the second cake layer on top.

2. Frost the second layer with buttercream.  Place the third cake layer on top.

3. Pipe a ring of buttercream around outer edge of third layer.  Spoon the remainder of the lemon curd into the center of the buttercream ring and spread evenly.

4. Top with fourth cake layer and then frost entire cake with the remaining buttercream.