LEMON-MERINGUE SHEET CAKE

Lemon-Meringue Sheet Cake image

This burnished beauty gets its flavor from fresh lemon zest, and its stature from not-too-sweet meringue. (More than half of the sugar gets boiled into a syrup that you beat into egg whites-the result is cool, thick, and silky.) Dollop tons on top for a dramatic presentation, and if you don't have a kitchen torch, brown the peaks with a quick blast under the broiler.

Provided by Martha Stewart

Categories Food & Cooking Dessert & Treats Recipes Cake Recipes

Time 2h15m

Yield Serves 10 to 12

Number Of Ingredients 12

Ingredients

1 stick unsalted butter, melted and cooled, plus more, softened, for pan
1 2/3 cups unbleached all-purpose flour
2 teaspoons baking powder
1 teaspoon kosher salt (we use Diamond Crystal)
4 large eggs, room temperature
1 1/2 cups sugar
4 teaspoons finely grated lemon zest (from 2 lemons)
2 teaspoons pure vanilla paste or extract
3/4 cup sour cream
1 1/3 cups sugar
1/4 teaspoon cream of tartar
4 large egg whites, room temperature

Steps:

Cake: Preheat oven to 350°F. Brush a 9-by-13-inch or 8-by-12-inch baking pan with butter. Line with parchment, leaving a 2-inch overhang on long sides. Butter parchment.
Whisk together flour, baking powder, and salt. Combine eggs and sugar in the bowl of a mixer fitted with the whisk attachment. Beat on high speed until thick and pale, about 4 minutes. Add flour mixture; beat just to combine. Add butter, lemon zest, and vanilla; beat to combine. Add sour cream; beat until smooth.
Scrape batter into prepared pan, smoothing top with a spatula. Bake until top springs back when lightly touched and a tester inserted in center comes out clean, 30 to 35 minutes (for 9-by-13-inch) or about 40 minutes (for 8-by-12).
Let cool in pan on a wire rack 10 minutes. Using parchment overhangs, lift cake out of pan and let cool completely on rack. (Cake can be made to this point and stored at room temperature, wrapped in plastic, up to 1 day.)
Meringue Frosting: Place 1 cup sugar, 5 tablespoons water, and cream of tartar in a small saucepan over medium heat. Bring to a boil, then cook 4 minutes. Meanwhile, beat egg whites on high speed to soft peaks, 2 to 3 minutes. Gradually add remaining 1/3 cup sugar, beating until sugar has dissolved. (If ready before sugar syrup, keep whites moving on lowest speed.)
With mixer running, gradually pour hot syrup into meringue (aim for side of bowl, and avoid beater). Continue beating until cool to the touch and very fluffy, 4 to 5 minutes. Spread over top of cake. Lightly brown with a torch (or under broiler about 30 seconds). Frosted cake is best the day it's assembled.