¾ cup coarsely ground yellow cornmeal
¼ cup unbleached all-purpose flour
1 tablespoon sugar
1 teaspoon baking powder
½ teaspoon salt
½ cup defrosted frozen or canned corn kernels, drained
2 tablespoons chopped pickled jalapeño peppers
½ cup buttermilk
5 tablespoons melted unsalted butter
1 large egg
Preheat your oven to 450°F. Put a 6-inch cast iron skillet in the oven for 15 minutes to heat. Meanwhile combine the cornmeal, flour, sugar, baking powder, and salt in a bowl. Stir in the corn and jalapeños. In a separate bowl, whisk together the buttermilk, 4 tablespoons of the butter, and the egg; stir the wet mixture into the dry ingredients until just blended.
Remove the skillet from the oven, brush with the remaining tablespoon of butter, and spoon in the batter, smoothing the top with a metal spatula. Bake until the top of the cornbread is golden and a toothpick inserted in the center comes out clean, 23 to 25 minutes. Remove, and let stand on a rack for a few minutes before inverting (or serve the cornbread out of the pan). Serve with softened butter.