Ultimate Pizza Sauce

This pizza sauce recipe was given to me as a wedding present, written on the inside cover of a pizza cookbook. It is thick, saucy, spicy and delicious. I'll never use anything else on my homemade pizzas. I like to double or triple it and put it in Ziploc bags in my freezer.
Ingredients:

2 tablespoons olive oil
1 tablespoon butter
1/2 cup onion, chopped
1/4 cup celery, chopped
1 garlic clove, minced
1 (8 ounce) can tomato sauce
1 (6 ounce) can tomato paste
2 tablespoons grated parmesan cheese
1 teaspoon dried basil
1 teaspoon dried oregano
1/2 teaspoon salt
1/2 teaspoon sugar
1/4 teaspoon black pepper
1 small bay leaf
1 teaspoon fennel seed

Directions:

In a large skillet, melt butter with the oil. Add the onion, celery and garlic and saute until soft and transparent.
Add tomato sauce and tomato paste and stir until smooth.
Add remaining ingredients and bring to slow simmer.
Simmer for 30-60 minutes (or not at all depending on your taste and time frame).
Remove the bay leaf and spread the sauce on your prepared pizza dough.