all-purpose flour, sifted
unsalted butter, melted and cooled
store-bought lemon curd
heavy whipping cream
- Spray the inside of a 4 1/2-inch springform pan. Place it on a baking sheet for easier handling; set aside.
- Place the buttermilk and baking soda in a small bowl, and whisk until the baking soda is dissolved. Add the egg yolk, vanilla, and melted butter, and whisk to combine.
- Place the flour, sugar, and salt in a medium-size mixing bowl and whisk to blend well. Add the buttermilk mixture, and whisk just until blended and smooth.
- Place the rack in the center of the oven, and preheat the oven to 350 degrees F.
- Spoon the batter into the prepared pan. Bake the cake until a toothpick comes out clean, about 25-30 minutes.
- Remove the baking sheet from the oven, and place the springform pan on a wire rack to cool for 15 minutes. After 15 minutes, take the cake out of the pan, and place it upright on the rack, letting it cool completely.
- To make frosting: Place the cream and confectioners' sugar in a small mixing bowl and beat on high speed until firm peaks form (about 2 minutes).
- Add half of the lemon curd and beat to mix.
- To frost: Cut the cake in half horizontally. Place the bottom half cut-side up. Spread the remaining lemon curd on the cake bottom, and a small amount of frosting on top of that.
- Place the other half of the cake, cut side down, on top of that. Frost the tops and sides of the cake.
- Keep refrigerated for up to 6 hours, and let the cake return to room temperature before serving.