Soak bread cubes in milk until saturated (approximately 5 minutes).

Squeeze excess milk from the bread.

Combine soaked bread with ground beef, rice, parsley, sage, garlic, sugar, salt, and pepper in a large mixing bowl.

Mix the filling ingredients well and refrigerate.

Steam the cabbage until the outermost leaves are pliable (5-10 minutes).

Peel off at least 12 cabbage leaves.

Pare the thick part of the rib of each cabbage leaf to flatten it.

Place a small amount of filling in the center of each cabbage leaf.

Fold the sides of the leaf over the filling, overlapping slightly.

Roll up the leaf into a compact bundle, starting at the stem end.

Repeat the rolling process until all leaves and meat mixture have been used.

Preheat the oven to 400°F (200°C).

Heat a large Dutch Oven over medium-high heat.

Add olive oil, onion, and garlic to the Dutch oven and saute until translucent.

Add tomato paste and paprika to the Dutch oven and saute for 3 minutes.

Stir in chicken stock, tomatoes, balsamic vinegar, sugar, and sage to the Dutch oven.

Season the sauce to taste with salt and pepper.

Simmer the sauce for 5 minutes.

Remove 1 cup of the sauce to a measuring cup.

Arrange the stuffed cabbage leaves neatly in a single layer over the remaining sauce in the Dutch Oven.

If there is extra filling, make meatballs and tuck them in around the rolls.

Pour the 1 cup of reserved sauce over the rolls.

Transfer the Dutch Oven to the preheated oven and bake until the bundles are cooked through and firm to the touch (25 to 30 minutes).

Use a large spoon to transfer the rolls to a platter or storage container.

Puree the remaining sauce together with the sour cream using an immersion blender.

Serve the cabbage rolls with mashed potatoes or rice.