In large casserole pot, heat the oil over a medium-high flame.

Add onions and garlic and sauteed until onions are translucent (about 10 minutes).

Add celery, carrots, and 1/2 teaspoon of each salt and pepper.

Sauteed until all vegetables are soft (about 10 minutes).

Add tomatoes and bay leaves and simmer uncovered over low heat until sauce thickens (about 1 hour).

Remove and discard bay leaves.

Season sauce with more salt and pepper, to taste. (recommend 1/2 more of each).

Sauce can be made a day in advance. Cool, then cover and refrigerate. Rewarm over medium heat before using.