Step 1

In a medium size heavy pot, heat the oil over medium heat. Add the onion and garlic and saute until soft and translucent, about 3 minutes. Add the celery, carrot (optional) and season with salt and pepper. Saute until all the vegetables are soft, about 5 minutes.

Step 2

Add the tomatoes, rinsed capers, basil, and bay leaf. Smush the tomatoes with a wooden spoon. Simmer covered on low heat for about an hour or until thick. Remove the bay leaf and check for seasoning.

Step 3

To smooth out any type of acidic taste add 1 Tablespoon of the butter and mix until melted. Taste again and if you think it's needed add the other Tablespoon of butter. This should round out the flavors.