- 1 (10.75 ounce) can condensed tomato soup (such as Campbell's®)
- 1 (46 ounce) can tomato-vegetable juice cocktail (such as V8®)
- 3 tablespoons Worcestershire sauce, or to taste
- 1/4 cup dried onion flakes
- 2 tablespoons dried parsley
- 2 tablespoons prepared horseradish
- 1 tablespoon extra-hot Dijon mustard
- 2 teaspoons garlic powder, or to taste
- 1/4 teaspoon black pepper
- 3 tablespoons instant tapioca
- 2 cups water
- Mix together the tomato soup, vegetable juice cocktail, Worcestershire sauce, onion flakes, dried parsley, horseradish, Dijon mustard, garlic powder, black pepper, tapioca, and water in a slow cooker. Set the cooker on Low, and cook until thickened, 3 to 4 hours.