Begin by preheating your oven to 400°F (200°C). Prepare a muffin tin by lining it with paper liners or lightly greasing each cup with cooking spray or butter to prevent sticking.
In a large mixing bowl, combine the cornmeal, all-purpose flour, baking powder, and salt. Using a whisk, blend these dry ingredients thoroughly until there are no lumps.
Add the granulated sugar, shredded cheddar cheese, and finely chopped jalapeños to your dry mixture. Stir them in gently to ensure they are evenly distributed throughout the flour mixture.
In a separate bowl, whisk together the buttermilk, vegetable oil, and lightly beaten eggs until the mixture looks uniform and creamy.
Pour the wet ingredients into the bowl with the dry ingredients. Carefully fold everything together with a spatula or wooden spoon until the dry ingredients are just moistened. Aim for a few lumps; overmixing can lead to tough muffins.
Using a spoon or a muffin scoop, divide the batter evenly into the prepared muffin cups, filling each one about two-thirds full to allow for rising.
Place the muffin tin in the preheated oven and bake for 15-18 minutes. They are done when the tops are golden brown and a toothpick inserted into the center comes out clean.
Once baked, remove the muffins from the oven and let them cool in the pan for about 5 minutes. Afterward, carefully transfer the muffins to a wire rack to cool completely.
Notes
Serve warm with honey butter or a spicy dip. Garnish with a fresh slice of jalapeño.