Fluffy Lemon Buttermilk Cake
Filled with store-bought jam and frosted with whipped cream, these cake squares are simple to make and not too sweet. Bake the sheet cake ahead of time, then split, layer, and frost the day of the party.
- 1 cup (2 sticks) unsalted butter, softened plus more for baking dish
- 3 cups all-purpose flour
- 1 tablespoon baking powder
- 1/2 teaspoon salt
- 2 cups granulated sugar
- 4 large eggs
- Finely grated zest of 1 lemon, (about 1 tablespoon)
- 1 teaspoon pure vanilla extract
- 1 cup low-fat buttermilk
- 10 ounces seedless raspberry jam, (1 cup)
- 1 cup heavy cream
- 3 tablespoons confectioners' sugar
Preheat oven to 325 degrees. Butter and flour a 9-by-13-inch glass baking dish, and set aside. Whisk together flour, baking powder, and salt in a medium bowl; set aside.
Using an electric mixer, beat butter and granulated sugar in a mixing bowl until pale, about 2 minutes. Add eggs one at a time, mixing well after each addition. Mix in zest and vanilla.
Mix in flour mixture in three batches, alternating with two batches of buttermilk. Mix until just combined, scraping down bowl as needed. Spread batter evenly in prepared baking dish.
Bake until golden brown and a toothpick inserted into center of cake comes out clean, about 1 hour. Let cake cool completely in dish on a wire rack. Invert cake onto a baking sheet to remove from baking dish; then re-invert so cake is top side up.
With a long serrated knife, halve cake horizontally. Spread jam on bottom half; replace top half. Whip cream and confectioners' sugar in a medium bowl until slightly stiff peaks form. Spread frosting over cake, swirling decoratively. Refrigerate cake 30 minutes. Trim edges with serrated knife; cut into individual pieces and serve in eclair cups.