The combination of cake flour and all-purpose flour produces a very tender crumb. You will need a paper cornet to pipe the dots and lines of lemon curd that top the buttercream frosting. Fully decorated, the cake looks fresh and whimsical-a perfect choice for a birthday party, baby shower, or other celebration.

　　

Ingredients

makes one 9-inch layer cake

　　2 sticks (1 cup) unsalted butter, room temperature, plus more for pans

　　1 1/2 cups all-purpose flour, plus more for pans

　　1 1/2 cups cake flour (not self-rising)

　　1 tablespoon baking powder

　　1/2 teaspoon salt

　　1 cup sour cream or crème fraîche

　　Finely grated zest of 2 lemons (about 2 tablespoons)

　　2 tablespoons freshly squeezed lemon juice (about 1/2 lemon)

　　2 cups sugar

　　4 large eggs

　　2 recipes Lemon Curd (page 390), 3/4 cup reserved for piping

　　Lemon Swiss Meringue Buttercream (page 386)

　　

Step 1

Preheat the oven to 350°F. Butter two 9-by-2-inch round cake pans; line the bottoms with parchment paper. Butter parchment, and dust with flour, tapping out excess; set aside. Into a medium bowl, sift together the flours, baking powder, and salt; set aside. In a small bowl, combine sour cream with lemon zest and juice; set aside.

　　

Step 2

In the bowl of an electric mixer fitted with the paddle attachment, beat the butter on medium-high speed until fluffy, about 1 minute. Add sugar, and continue beating until light and fluffy, 4 to 5 minutes, scraping down the sides of the bowl as needed. Add eggs, one at a time, beating for 1 minute after each addition.

　　

Step 3

With the mixer on lowest speed, add the flour mixture in four parts, alternating with the sour cream mixture and beginning and ending with the flour mixture; beat until just combined, being careful not to over-mix.

　　

Step 4

Divide batter between prepared pans, and smooth with an offset spatula. Bake, rotating pans halfway through, until cakes are golden and pull away from sides of pan, and a cake tester inserted in the centers comes out clean, 30 to 35 minutes. Transfer pans to a wire rack to cool 20 minutes. Run a knife or thin metal spatula around edges of the pans. Invert cakes onto the rack; peel off the parchment. Reinvert cakes and let them cool completely, top sides up.

　　

Step 5

Using a serrated knife, trim tops of the cakes to make level. Slice each layer in half horizontally into two layers. Place one of the bottom layers on a cake plate, and spread 1/2 cup Lemon Curd over the top. Repeat with remaining cake layers and curd, leaving final cake layer uncoated. Spread a thin layer of Lemon Swiss Meringue Buttercream over the entire cake to seal in crumbs; refrigerate until well chilled, about 30 minutes.

　　

Step 6

Using an offset spatula, spread entire cake with remaining buttercream. Refrigerate 30 minutes before decorating with Lemon Curd: Using a paper cornet filled with curd, pipe dots of varying sizes on top of the cake. Starting at the bottom, pipe vertical lines of varying lengths up the side of the cake. Cake can be kept in the refrigerator, covered with a cake dome, for up to 3 days.

　　Reprinted with permission from Martha Stewart's Baking Handbook by Martha Stewart. © 2005 Clarkson Potter