Place tomatoes on a baking sheet and place under broiler. Cook until skin begins to peel and turn black. Remove from heat and allow to cool.
Heat Olive Oil in large pan over medium heat. When oil is warm, add onion and saute until cooked through, about 5 minutes. Add garlic and saute about a minute longer.
Brown Italian Sausage in a separate skillet, breaking apart as it cooks. When fully browned and no more pink remove from heat and drain.
Meanwhile, Puree roasted tomatoes and add to onion mixture along with water and seasonings. Simmer for about 20 minutes. Stir in cooked sausage.
Serve over your favorite pasta.