- 1 1/2 cups all-purpose flour
- 1 1/2 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 1 stick (1/2 cup) unsalted butter, softened
- 1 cup plus 3 tablespoons granulated sugar
- 1 teaspoon vanilla
- 1/4 teaspoon almond extract
- 2 large eggs
- 1/2 cup sour cream
- 2 medium firm-ripe nectarines (14 to 16 ounces), quartered lengthwise and pitted
- 1 tablespoon fresh lemon juice
- 2 teaspoons confectioners sugar for dusting
- Preheat oven to 350°F. Butter and flour a 13- by 9- by 2-inch metal baking pan, knocking out excess flour.
- Sift together flour, baking powder, baking soda, and salt into a small bowl. Beat together butter and 1 cup granulated sugar in a large bowl with an electric mixer at medium-high speed until pale and fluffy, about 2 minutes, then beat in vanilla and almond extract. Add eggs 1 at a time, mixing at low speed after each addition until just combined. Add flour mixture and sour cream alternately in 3 batches, mixing after each addition until just combined. Spread batter in pan, smoothing top.
- Cut nectarines lengthwise into 1/8-inch slices and toss with lemon juice and remaining 3 tablespoons granulated sugar in a bowl. Arrange slices, overlapping slightly, in 4 crosswise rows over batter. Cover surface of cake with a piece of buttered wax paper (paper helps fruit glaze itself) and bake in middle of oven 15 minutes. Remove paper and bake until a tester comes out clean, 20 to 25 minutes more.
- While cake is still warm, dust generously with confectioners sugar, then cool completely on a rack.