In a large saucepan over medium heat, melt the butter and sweat the onion and garlic until translucent, about 3 minutes. Add the tomatoes and simmer 15 minutes. Add the remaining ingredients and simmer 20 minutes.
Puree the mixture in a food processor, pour into a bowl, and let cool at room temperature. May be refrigerated up to 1 week or frozen.
Recipe courtesy of Bobby Flay