Peel off the skin of tomato and roughly chop

Peel yellow onion and cut in half lengthwise

In a sauce pan, put in tomato, onion, butter, salt and oregano to a boil.

Once boiling, reduce to a steady simmer and simmer for 45 minutes. Stir occasionally to avoid sticking to the pan. You will know that its done when the tomato has broken down and the butter separates from the sauce.

Toss in your choice of pasta and add parmesan cheese as desired.