Step 1

Preheat oven to 375°F. Toss together peaches, cinnamon, and 1/4 cup of the sugar in a medium bowl; let stand at room temperature until ready to use.

Step 2

Place butter in a 10-inch cast-iron skillet; place in preheated oven until butter is melted, about 10 minutes. Meanwhile, whisk together flour, baking powder, salt, and remaining 3/4 cup granulated sugar in a large bowl. Whisk in milk and vanilla until combined.

Step 3

Carefully remove skillet from oven, and pour in cake batter. (Do not stir.) Bake in preheated oven 5 minutes. Spoon peaches and any accumulated juices over cake batter. (Do not stir). Continue baking until golden brown and cake is slightly firm to touch, 25 to 30 minutes. Serve warm with ice cream.