Heat oil in a large nonstick skillet over medium heat. Add onion and garlic; sauté 3 minutes. Add remaining ingredients, and bring to a boil, stirring occasionally. Reduce heat, and simmer 10 minutes, stirring occasionally. Serve over pasta or polenta, or on crostini.
Our sauce didn't have a lot of flavor, but that may have been our fault. We were using grocery store tomatoes and dried herbs, and had to omit the garlic due to an allergy. I may try this again with garden tomatoes.