This cake, inspired by the great baker Maida Heatter’s recipe, gets hits of lemon three times: zest and juice in the cake, a clear soaking syrup that seeps into the cake and, finally, a creamy, thick glaze that coats the top. This cake is fluffy, supremely moist and has a grown-up vibe about it: not kiddie stuff. The buttermilk in the cake adds even more tang and is essential to the rise and delicate crumb. Leftover buttermilk freezes well, so store it in the freezer for your next baking project if you don’t plan to use the rest of the quart anytime soon.
Lemon Buttermilk Sheet Cake
1 hour and 15 minutes, plus cooling. Serves 12 to 16.
For the cake:
- Nonstick baking spray
- 2 cups all-purpose flour
- 1 teaspoon fine sea salt
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- 2 cups granulated sugar
- ½ cup vegetable oil
- ⅔ cup buttermilk
- Finely grated zest of 2 lemons, plus more to garnish
- 6 tablespoons fresh lemon juice
- 1 teaspoon pure vanilla extract
- 4 large eggs
For the syrup and glaze:
- 1 ¼ cups plus 2 tablespoons powdered sugar
- 3 tablespoons plus 2 teaspoons fresh lemon juice
- 2 tablespoons unsalted butter, melted
- 1 tablespoon whole milk
- Heat the oven to 350 degrees. Grease a 9-by-13-by-2½-inch metal baking pan with baking spray.
- In a medium bowl, whisk together the flour, baking soda and salt. In a large bowl, whisk together the sugar, oil, buttermilk, lemon zest and juice and eggs until smooth. Add the dry ingredients to the liquid ingredients and whisk until just combined. Pour the batter into the prepared pan and smooth the top. Bake until golden brown on top and a toothpick inserted in the center of the cake comes out clean, 35 to 40 minutes.
- While the cake is in the oven, make the syrup and glaze: In a small bowl, whisk together 1/4 cup powdered sugar and 3 tablespoons lemon juice until they form a thin syrup. In a medium bowl, whisk together the remaining 1 cup plus 2 tablespoons powdered sugar and 2 teaspoons lemon juice, the butter and milk until they form a thicker, smooth glaze.
- Remove the pan from the oven and let the cake cool for 5 minutes. Using a toothpick or the tines of a fork, poke the cake all over. Slowly drizzle the syrup evenly over the cake and let the cake cool completely.
- Scrape the glaze onto the cake and use a spoon to spread it evenly over the top. Scatter more lemon zest over the cake, if you like, to garnish. Let the cake stand for 10 minutes to set the glaze before serving from the pan.
The cooled, syrup-soaked cake can be wrapped in plastic wrap and kept at room temperature for up to 2 days. The syrup and glaze can be refrigerated separately for up to 5 days. Reheat the syrup before using on the warm cake. Return the glaze to room temperature before whisking again and using.