Preheat the olive oil to medium heat for 3 minutes. Add the onions, garlic, carrots, and celery. Season lightly with salt and pepper and cook for 10 to 12 minutes until the vegetables are soft.
Add in the roasted red pepper and all of the remaining ingredients. Bring to a boil, reduce heat to simmer and taste for salt and pepper. Continue cooking at a low simmer for a good 45 to 50 minutes until the sauce thickens and reduces.
Now for the next step, I used a hand blender, but you can also blend sauce in batches in a regular blender. Blend the warm sauce and cook for another 10 minutes. Yields up to 8 servings. I like to use this sauce for any pasta dish or as a pizza sauce. Cool completely for refrigerating or freezing.