Heat oil in large, heavy nonaluminum saucepan over medium heat. Add the onion and garlic; sauté for 5 minutes or until the onion is softened.
Stir in the tomatoes, vinegar, brown sugar, Worcestershire sauce, black pepper, chili powder, salt, liquid smoke, cumin and red pepper until well blended. Bring to boiling. Reduce the heat; simmer, uncovered, for 2 hours or until the mixture is thickened, stirring occasionally. Toward the end of cooking, make sure to stir frequently so that the sauce doesnt scorch on the bottom of the saucepan.
Let the sauce cool slightly. Working in batches, spoon the sauce mixture into a blender or food processor. Whirl until pureed.
Transfer the sauce to a container with a tight-fitting lid. Let cool completely, uncovered. Then seal tightly.
Refrigerate the sauce for up to 2 weeks. Use in your favorite rib or grilled chicken recipe, or spoon over burgers, hot dogs or grilled fish. Makes 6 cups.