1 cup all-purpose flour, spooned into measuring cup and leveled off with knife
1 teaspoon baking powder
1/4 teaspoon salt
1/2 cup (1 stick) unsalted butter, room temperature
2/3 cup granulated sugar, plus more for sprinkling over cake
2 large eggs
1 teaspoon pure vanilla extract
3 tablespoons dark rum
2 sweet baking apples, peeled, cored and cut into 1/2-inch cubes (such as honeycrisp, fuji or golden delicious)
Confectioners' sugar (optional)
1. Preheat oven to 350 degrees F. Spray a 9-inch springform or regular cake pan with nonstick cooking spray.
2. Whisk together flour, baking powder and salt in a small bowl.
3. Using a handheld mixer with beaters or stand mixer with paddle attachment, cream butter and sugar until light and fluffly, about 3 minutes. Add eggs, one at a time, beating well and scraping down sides of bowl after each addition. Beat in vanilla and rum. Don't worry if the batter looks grainy. Add the flour mixture and mix on low speed until just combined. Using a rubber spatula, fold in chopped apples.
4. Pour batter into prepared pan and sprinkle evenly with 1 tablespoon of granulated sugar. Bake cake for about 40 minutes, or until cake is lightly golden and toothpick inserted in the center comes out clean. Allow cake to cool until just warm. Run a blunt knife around the edges of the cake and remove sides of springform pan if using. Dust with Confectioners' sugar if desired. Cake can be served warm or room temperature, with or without lightly sweetened whipped cream or vanilla ice cream.