Pizza Sauce

1 medium yellow onion
4 cloves garlic, minced
1/2 green pepper, finely diced
5-6 button mushrooms
14 ounce can of tomato sauce (400ml)
1½ tsp dried oregano (8ml)
fresh ground black pepper and salt to taste
olive oil

Sauté the onion and garlic in a little oil, adding the mushrooms and pepper after two or three minutes.
Add the sauce and seasonings and simmer for 15 - 20 minutes until thick, stirring constantly.

Can be stored, covered, in the refrigerator for a few days.