Orange Marmalade Layer Cake

After the cakes are soaked in fresh orange syrup, they become moist and tender. Carefully transfer them to a serving dish for frosting.
Preheat the oven to 350 degrees.Brush 2 (9-inch) round cake pans with cooking spray and line the bottom of the pans with waxed paper.Lightly pour the sifted cake flour into dry measuring cups; smooth with a knife. Combine the sifted flour, baking soda, and salt, stirring with a whisk. Put the butter in a large bowl and beat with a mixer on medium speed until light and fluffy (about 2 minutes). Gradually add 1 3/4 cups sugar, 1 tablespoon at a time, whisking until smooth. Add the orange zest and vanilla. Add the egg whites 1 at a time, beating thoroughly after each addition.Mix buttermilk and milk. Add the flour and buttermilk mixture alternately to the butter mixture, starting and ending with the flour mixture. Pour the batter into the prepared pans; tap sharply on the baking sheet once to remove any air bubbles. Bake at 350 ° C for 25 minutes or until a wooden stick inserted in the center comes out clean. Cool in tins for 20 minutes on a wire rack; remove from tins. Cool completely on a wire rack.Combine the juice and 1/4 cup sugar; stir until the sugar is dissolved. Plentifully pierce the cake layers with a wooden stick. Slowly drizzle the cake layers with the juice mixture.Carefully place 1 layer on a plate; spread with 1/3 cup of marmalade. Spread the remaining layer; spread the remaining marmalade on top of the cake. Add sour cream to the whipped filling; spread on the sides of the cake. Cover and refrigerate for at least 2 hours.