01 - Preheat oven to 400°F (204°C) and grease a standard 12-cup muffin tray.
02 - Whisk together flour, cornmeal, sugar, baking powder, baking soda, and salt in a large mixing bowl.
03 - In a separate bowl, beat eggs. Add milk and melted butter; whisk until fully blended.
04 - Pour wet ingredients into the dry ingredients. Stir until just combined; avoid overmixing.
05 - Gently fold in cheddar cheese, diced jalapeños, and corn kernels until evenly distributed.
06 - Spoon batter evenly into prepared muffin tray, filling each cup about three-quarters full.
07 - Bake in preheated oven for 18–20 minutes or until tops are golden and a toothpick inserted into the center comes out clean.
08 - Allow muffins to cool in pan for 5 minutes before transferring to a rack. Serve warm.