1 thinly sliced jalapeño and extra cornmeal, for decorating
Preheat your oven to 425°F [220°C]. Prep a muffin tin with 12 parchment liners.
In a large mixing bowl, whisk together the cornmeal, flour, baking powder, and salt. In a medium mixing bowl, whisk together the eggs, butter, olive oil, buttermilk, sugar, minced jalapeños, and most of the cheddar. Pour the wet ingredients over the dry ingredients, and stir to combine (do not overmix).
Evenly distribute the batter among the 12 lined muffin cups. Decorate the tops with jalapeño slices, cheese, and a light sprinkling of cornmeal. Bake for 20 minutes, until a toothpick inserted in the center comes out cleanly.
Let cool on a rack or clean, dry towel. Muffins keep well at room temperature for a couple days. But they keep much better in the freezer, so freeze any ones you don’t plan to eat in the first day or two.
* If you want it to be pretty spicy, only de-rib them partially, or leave the piths intact for a ton of spice. The heat comes almost entirely from the white pith, and less so from the green flesh and seeds.