1. Preheat oven to 425º F.
2. Butter the sides of non-stick muffin tins using the additional room temperature butter.
3. In a medium mixing bowl, mix cornmeal, flour, baking powder, baking soda and salt.
4. In a separate bowl, whisk together eggs, egg yolk and buttermilk.
5. Add the buttermilk mixture to the cornmeal mixture and stir just until combined. Add the melted butter, jalapeño, red peppers, corn kernels and cheese. Stir to combine.
6. Fill each muffin ¾ full. Bake for 15-20 minutes or until lightly browned and when tested with a cake tester, the cake tester comes out clean (i.e. no batter is adhering to the cake tester).
7. Let cool for 5 minutes, then unmold. Serve while hot.
Note: If you desire muffins with less heat, remove all the seeds and white membrane. This is where the heat of the chile is. If you want the all the heat, simply mince up an entire chile. Be sure to wash hands immediately after handling chilies as they can be very irritating to the skin.