Boil a large pot of water. Blanch cabbage leaves 2–3 minutes until flexible. Drain and cool. Trim thick ribs.
Warm olive oil in a skillet over medium heat. Sauté onion until translucent, then stir in garlic for 30 seconds.
Combine ground beef, ground pork, cooked rice, half the onion mixture, parsley, salt, pepper, paprika, and thyme. Mix gently.
Whisk tomato sauce, crushed tomatoes, tomato paste, beef broth, brown sugar, Worcestershire, vinegar, and remaining onions in a bowl.
Spread 1 cup of the sauce in the bottom of the slow cooker.
Spoon about 1/3 cup filling onto a cabbage leaf. Fold sides over and roll snugly. Repeat with remaining leaves and filling.
Arrange rolls seam-side down in the cooker. Pour remaining sauce over the top to cover evenly.
Cover and cook on Low for 6 hours (or on High for 3–4 hours) until the meat is cooked through and tender.
Let rest 10 minutes before serving. Spoon extra sauce over each roll and garnish with parsley if desired.
Notes
Variation: Swap the pork for ground turkey and add a pinch of smoked paprika for a lighter, smoky twist. For a little heat, stir 1/4 tsp crushed red pepper into the sauce.Storage: Refrigerate leftovers in an airtight container for up to 4 days, or freeze for 2–3 months. Reheat gently with a splash of broth or sauce.This recipe is an original creation inspired by classic Crock Pot Cabbage Rolls Recipe flavors. All ingredient ratios and instructions are independently developed.