Created by Judeka on August 20, 2015
Step 1: Whisk the egg yolks and sugar together either in the top of a double boiler or a heatproof large heatproof bowl immersed in a saucepan filled with one inch of water.
Step 2: Add 1/3 cup of lemon juice and the zest from the 4 lemons and continue to stir, using a silicone spatula, cooking about 8-10 minutes until the mixture thickens slightly.
Step 3: Remove from the heat and add the butter one tablespoon at a time, stirring each until it is melted and smooth.
Step 4: Once all the butter has been added pour the lemon curd into a bowl, cover and refrigerated until thickened and cooled for about 2 hours.
Step 5: If there is any extra the curd will keep about 2 weeks refrigerated.
Step 6: Preheat oven to 350F.
Step 7: Cut parchment paper circles to fit two 9 inch cake pans and lightly grease the papers with butter. Set aside.
Step 8: In small bowl using an electric mixer on low, mix the egg whites, 1/4 cup buttermilk and lemon zest. Set aside.
Step 9: In a large mixing bowl, using an electric mixer, beat butter and sugar until creamy, about 2-3 minutes.
Step 10: Add in dry ingredients and mix until combined.
Step 11: Slowly bet in the egg white mixture. Beat in remaining buttermilk.
Step 12: Pour evenly into the prepared cake pans and place in the preheated oven on the middle rack.
Step 13: Bake for about 25-28 minutes, or until toothpick inserted in the center of the cake comes out clean.
Step 14: Remove and cool in cake pans 5 minutes.
Step 15: Invert onto a wire rack and cool completely before frosting.
Step 16: In a mixing bowl, use an electric mixer on medium speed to beat the butter, cream cheese, confectioners' sugar and 2 tablespoons of lemon curd in a mixing bowl for 3-5 minutes, until fluffy. Set aside.
Step 17: In a small bowl, use your hands to mix topping ingredients until crumbly. Just rub the topping mixture between your hands until it is a good texture. Set aside.
Step 18: Lay first layer of cake on a cake plate. Add 1/2 cup dry cake topping. Frost middle layer with all but 1/2 cup of cream cheese filling.
Step 19: Top with second layer of cake. Spread remaining 1/2 cup cream cheese filling. Sprinkle the crumb topping over the entire top of the cake. Refrigerate at least two hours.