Instructions

1. 1
   Place a 10-inch cast-iron skillet in the oven and preheat to 400°F (204°C).
2. 2
   In a large bowl, whisk the cornmeal, flour, sugar, baking powder, and salt together.
3. 3
   In a medium bowl, whisk together the buttermilk, eggs, and melted butter.
4. 4
   Pour the wet ingredients into the dry ingredients and stir gently with a spatula until just combined.
5. 5
   Fold in the shredded cheddar cheese and diced jalapeños.
6. 6
   Carefully remove the hot skillet from the oven.
7. 7
   Drop a tablespoon of butter into it and swirl to coat the bottom and sides thoroughly.
8. 8
   Pour the cornbread batter into the hot skillet, smoothing the top.
9. 9
   Arrange optional jalapeño slices decoratively over the surface.
10. 10
    Bake for 20 to 25 minutes until the top is golden brown and a toothpick inserted into the center comes out clean.
11. 11
    Serve warm.