Pasta with Spicy Cheesy Tomato Sauce

This is a basic tomato sauce pasta with a bit of spiciness in the sauce.

Ingredients:
1 jar of marinara sauce (we will upgrade this to something more awesome)
1/2 white or yellow onion
Garlic! I used about 8 cloves
1 jalapeno
Some red pepper flakes
1 tablespoon of butter
3/4 lb pasta (I used whole wheat penne)
Mozzarella Cheese