Step 1

Preheat oven to 350°. Heat 3 Tbsp. butter and brown sugar in a large cast-iron skillet over medium heat, stirring until sugar dissolves. Stir in cranberries; remove from heat.

Step 2

Beat together granulated sugar and remaining 8 Tbsp. (1 stick) butter until light and fluffy, about 4 minutes. Add eggs one at a time, beating to blend after each addition. Stir in sour cream. Whisk together flour, cornmeal, baking powder, and salt; mix into egg mixture. Scrape batter over cranberries in pan and bake until golden brown and a tester inserted into the center comes out clean, 25–30 minutes. Invert immediately onto a wire rack (sugared fruit will stick to pan if left to cool).