1. Place bacon in a large Dutch oven; cover with 8 cups water. Bring to a boil; cover, reduce heat, and simmer 2 hours, skimming foam from liquid as necessary.
2. Remove bacon from pan; cover and keep warm. Remove 1 1/4 cups cooking liquid from pan; reserve cooking liquid for mustard sauce. Discard the remaining cooking liquid.
3. Add red potatoes, carrots, and cabbage to pan; cover with the remaining 6 cups water. Bring to a boil. Cover and simmer 20 minutes or until vegetables are tender; drain. Cut each cabbage quarter in half lengthwise.
4. Melt butter in a medium saucepan over medium heat. Add onion and garlic; cook 3 minutes or until tender, stirring occasionally. Stir in wine and mustard; cook 2 minutes. Add reserved 1 1/4 cups bacon cooking liquid and milk. Bring to a boil; cook 20 minutes or until reduced to 2 cups, stirring frequently. Stir in black pepper and salt. Cut bacon into 8 slices; serve with sauce and vegetables.