Drain whole peeled plum tomatoes, and crush tomatoes. Melt butter in a small saucepan over medium-high heat. Add onion, and sauté 3 minutes. Add smashed garlic cloves, and sauté 1 minute. Stir sugar, cider vinegar, white vinegar, tomato paste, kosher salt, Worcestershire sauce, freshly ground black pepper, and crushed tomatoes into onion mixture; bring to a boil. Reduce heat to low; simmer, stirring occasionally, 2 hours or until color is deep red and most of liquid has evaporated. Remove from heat, and let mixture stand 15 minutes. Process mixture in a blender or food processor until smooth. Spoon into 3 (8-oz.) glass containers. Store barbecue sauce in refrigerator up to 3 weeks.
PACKAGE IN: Square Swingtop 8.5-oz. Bottle ($2.28; specialtybottle.com)