Apple-Ginger Upside-Down Cake

Ingredients

• For topping
• 2 medium, tart apples
• Cooking spray
• ½ cup unsalted butter
• ¾ cup brown sugar
• 1 teaspoon ground cinnamon
• For batter
• ½ cup unsalted butter
• 3 tablespoons crystallized ginger
• 2 large eggs
• 1 ½ cups all-purpose flour
• 1 ½ teaspoons baking powder
• ½ teaspoon baking soda
• ¼ teaspoon kosher salt
• 1 cup granulated sugar
• 1 tablespoon vanilla extract
• ½ cup buttermilk, divided
• ½ gallon vanilla ice cream (optional for serving)

Steps

1. Prepare topping. Peel and core apples, then slice thinly. Coat 10-inch cast-iron skillet (or oven-safe pan) with spray. Add butter, brown sugar, and cinnamon; place on medium. Cook 3–5 minutes, stirring continuously, until butter melts and sugar dissolves; remove from heat. Arrange apple slices in single layer on top, pressing carefully into mixture; set aside.
2. Prepare batter. Set butter out to soften. Preheat oven to 375°F. Chop ginger finely. Separate eggs; place egg whites in medium bowl. Combine in second medium bowl: flour, baking powder, baking soda, and salt. Beat butter and sugar with electric mixer until pale yellow and fluffy. Beat in vanilla, ginger, and egg yolks. Mix in one-third flour mixture until just blended, then add ¼ cup buttermilk. Repeat with remaining flour mixture and buttermilk until blended (do not overmix).
3. Beat egg whites with electric mixer until soft peaks form. Add egg whites to batter in batches, folding until just incorporated (do not overmix). Add batter to skillet; smooth into even layer over apples.
4. Bake 30–40 minutes until toothpick inserted in center comes out clean. Remove skillet from oven; let stand 10 minutes to cool. Loosen edges with thin spatula, then carefully invert cake onto serving platter. Serve with ice cream, if using.