Prepare Sour Cream White Cake according to the recipe, substituting 1 tsp. vanilla for 1 tsp. lemon extract and 1 tbsp. fresh lemon zest.  Bake and cool.  Cut each 8-inch layer into halves for total of four 8-inch cake layers. Set aside for filling and icing. 

Prepare Sweet Strawberry Filling according to the recipe.  Be sure the filling has a jammy consistency and is cool before filling.

Prepare Lemon Curd 1.0 using the 4 egg yolks remaining from the Sour Cream White Cake recipe.  Cool and reserve for filling the cake. 

Prepare Lemon Curd 2.0 according to the recipe.  Cool and set aside to mix in with the Italian Meringue Buttercream Frosting. 

Prepare Italian Meringue Buttercream Frosting according to recipe.  Prepare Lemon Variation by mixing all of Lemon Curd 2.0 recipe evenly into frosting. 

Assemble the cake:

Place 1 cake layer on a serving plate.  Using an icing bag fitted with a circular tip, or a zip-top gallon bag with a corner snipped off, pipe a border of Italian Meringue Buttercream around the cake layer.  Spread half of the Sweet Strawberry Filling evenly inside this icing border.  Cover with a second cake layer.

Again, pipe an icing border on the second cake layer.  Using all of Lemon Curd 1.0 recipe (approximately 3/4 cup), evenly spread lemon curd inside the icing border. Top with a third cake layer. 

Repeat icing border on the third cake layer.  Evenly spread remaining strawberry filling inside the icing border. Top with a fourth cake layer. 

Using Lemon Curd 2.0 and Italian Meringue Buttercream Frosting mixture, frost top and sides of the cake layers as desired. 

As with any fruit-filled layer cake, refrigerate leftovers for up to a week in a tightly covered or plastic wrapped container.