Preheat oven to 400° and line a muffin pan with cupcake liners or spray with a non stick cooking spray. Set aside.
In a medium bowl, whisk together flour, baking powder, and sugar.
In a large bowl, whisk egg, milk and oil together.
Add the dry ingredients to the wet ingredients and stir just until combined (batter will be lumpy).
Next, fold cheese and diced jalapenos into batter.
Fill muffin pan or cupcake liners ⅔ full.
Bake for 20-25 minutes or until toothpick inserted comes out clean.
Remove from muffins from pan and serve warm.