Jalapeño Cheddar and Scallion Cornbread

1. Preheat oven to 425ºF. Brush the bottom of a cast-iron skillet (no larger than 10″) or square baking pan with oil or some butter.
2. In a large bowl, whisk together the cornmeal, flour, sugar, baking soda, and salt.
3. Stir in the jalapeños, scallions, and shredded cheddar.
4. In another bowl, whisk together the egg and buttermilk.
5. Stir in melted butter.
6. Stir buttermilk mixture into the cornmeal mixture until just moistened. Do not overmix.
7. Spread batter into prepared pan in an even layer.
8. Bake 15-20 minutes, until golden on top and when a knife inserted into the center comes out clean.