2 to 3 jalapenos, roughly chopped with seeds, plus 1 to 2 jalapenos, sliced
2 cups grated Cheddar (about 8 ounces)
2 tablespoons unsalted butter
Preheat the oven to 350°F. Put a 12-inch cast iron skillet in the oven while it is preheating.
Add the cornmeal to a small skillet and toast over medium-high heat until it is very aromatic and starting to brown, about 1 minute.
Combine the flour, sugar, baking powder, baking soda, and salt in a medium bowl. Combine the buttermilk and eggs in a separate bowl. Slowly add the wet ingredients to the dry while mixing. Fold in half the Cheddar and the chopped jalapenos (to taste).
Remove the cast-iron skillet from the oven, then add the butter and swirl around until it is melted and coats the inside.
Transfer the batter to the hot skillet, cover with the sliced jalapenos (to taste) and the remaining 1 cup Cheddar, and bake until the corn bread is golden on top, brown on the sides, and a toothpick inserted in the middle comes out clean, 30 to 35 minutes.