Apricot Turnover Cake

Ingredients

• Baking spray
• 2 cups all-purpose flour
• 2 teaspoons baking powder
• 3/4 teaspoon salt
• 12 tablespoons unsalted butter, at room temperature
• 1 cup packed dark brown sugar
• 1 1/2 teaspoons pure vanilla extract
• 1 1/2 cups sugar
• 2 large eggs, separated and at room temperature
• 1 cup milk, at room temperature
• 8 apricots, pitted and sliced into 8 wedges

Directions

1. Move the oven rack to the center and heat the oven to 350 degrees F. Coat a 13- by 9-inch cake pan lightly with baking spray, add parchment to the bottom, then mist the parchment with baking spray as well.
2. Sift the flour, baking powder, and 1/2 teaspoon salt into a bowl, then put it aside.
3. Set a medium stainless steel skillet over medium heat and melt 4 tablespoons butter until it starts to foam, 3 to 4 minutes. Gently tilt and swirl the skillet every so often, and keep cooking until the foam settles down and browned bits begin to show on the bottom, 2 to 3 minutes more. Take the skillet off the heat, then mix in the dark brown sugar, 1/2 teaspoon vanilla, and the remaining 1/4 teaspoon salt; it should look like wet sand. Scatter this mixture evenly into the prepared pan.
4. In a large bowl, beat the sugar with the remaining 8 tablespoons butter on medium speed until the mixture is pale and fluffy, about 3 minutes. Beat in the egg yolks 1 at a time, mixing thoroughly after each one.
5. Turn the mixer down to medium-low and add the flour mixture in 3 batches, alternating with the milk. Pause to scrape the bottom and sides of the bowl with a rubber spatula whenever needed. Mix in the remaining 1 teaspoon vanilla just until incorporated, then set the batter aside.
6. Attach the whisk to the mixer. In a separate clean, dry bowl, whip the egg whites on medium-high speed until they form stiff but not dry peaks, about 2 minutes. Use a rubber spatula to fold the whipped whites into the cake batter.
7. Lay the apricot wedges in rows on top of the brown sugar layer. Spoon the batter over the apricots and spread it gently with a rubber spatula so the fruit is covered evenly.
8. Bake until a toothpick poked into the center of the cake comes out clean, 45 minutes to 1 hour. Set the pan on a cooling rack and leave the cake in the pan for 30 minutes. Carefully invert the pan onto a rimmed baking sheet or serving platter, then remove the parchment. Cool for another 15 to 30 minutes before serving.