Preheat your oven to 400°F and grease a 9-inch square baking pan with a few spritzes of non-stick cooking spray.
In a medium mixing bowl, stir together 1 ½ cups yellow cornmeal, 1 cup all-purpose flour, 3 Tablespoons white sugar, 1 ½ teaspoons baking powder, ¾ teaspoons baking soda, and 1 ½ teaspoons salt.
In another bowl, combine the wet ingredients: 1 ¼ cups buttermilk, 2 large eggs, 6 Tablespoons melted butter, and 2 Tablespoons olive oil.
Add the flour mixture to the wet ingredients and stir until just combined. Fold in most of the 1 ½ cups shredded sharp cheddar cheese (reserving some to sprinkle on top) and 4 to 5 seeded and diced jalapeño peppers.
Spread the cornbread mixture into the prepared pan and top with the remaining cheese. Bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out clean.
Let the cornbread cool for 10 minutes before serving.
