Step 1

Preheat oven to 400 degrees F.

Step 2

Heat 2 tablespoons oil in a large cast-iron skillet over medium-high heat. Add onion and chili powder; cook, stirring, until starting to soften, about 2 minutes. Add pork, zucchini and 1/4 teaspoon each salt and pepper and cook, stirring often, until the pork is no longer pink, 4 to 5 minutes. Add corn and tomatoes with their juice and cook until heated through, 3 to 4 minutes more. Remove from heat.

Step 3

Meanwhile, whisk cornmeal, baking powder and the remaining 1/4 teaspoon each salt and pepper in a medium bowl. Whisk egg, buttermilk and the remaining 2 tablespoons oil in another bowl. Stir the buttermilk mixture into the cornmeal mixture until combined. Spread the batter over the pork and vegetables. Transfer the pan to the oven.

Step 4

Bake until the cornbread is just cooked through, 15 to 20 minutes.