Preheat oven to 375 degrees. Spray or lightly grease 12 muffin tins (or use muffin wrappers). In a large bowl combine flour, cornmeal, sugar, salt and baking powder. Stir in egg, milk and oil until well combined. Add the jalapeno peppers and cheese and combine. Pour batter into muffin tins.
Bake in preheated oven for15-20 minutes, or until a toothpick inserted into the center of the muffins comes out clean.