• There are two different methods for preparing the cabbage leaves for rolling.
• One is to core the cabbage and steam the whole heads until tender. The other is to freeze the raw heads of cabbage in advance.
• The leaves will soften as they defrost, eliminating the need for steaming. The freezer method is much easier, but you do need to plan two days ahead.

Prepare The Cabbage Using The Freezer Method:

• Rinse the heads of cabbage and peel away the 2 outermost leaves and discard them.
• Pat each head dry and wrap them tightly with plastic wrap.
• Place the wrapped heads in a freezer bag and freeze until solid, 12 to 18 hours (depending on your freezer).
• Allow at least 24 hours for the cabbages to defrost in the refrigerator. Be sure to place a shallow pan under them as they release a lot of water as they thaw.

Prepare The Cabbage Using The  Steam Method:

• Remove the cores and 2 outermost leaves from each head of cabbage.
• Add 2 to 3 inches of water to a large pot fitted with a steaming rack.
• Bring the water to a boil and place a head (or two if the pot is large enough) of cabbage in the pot.
• Cover and steam for 12 to 15 minutes, or until the leaves are tender and pliable enough to separate and roll. It may be helpful to remove the cabbage midway through the cooking time, remove a few of the most tender outer leaves and return the head to the pot to finish cooking.

Trim the cabbage leaves:

• Continue preparing the cabbage leaves for rolling by removing them from the heads, layer by layer. Set the leaves aside, blotting any excess moisture with a kitchen towel as you work.
• Depending on the diameter of your cabbages, you will need between 30 and 40 leaves to accommodate the quantity of meat in this recipe. Reserve the remaining cabbage for chopping.
• To ensure easy rolling, you want to slice off the thickest portion of the center vein of each cabbage leaf (see photo above).
• To do this, turn each leaf outer side up and insert the point of a paring knife just under the thinnest part of the center vein and slice toward the bottom of the leaf, being careful not to cut all the way through. Reserve the veins to be chopped and added to the cooking pot.

Prepare the filling:

• Heat the olive oil in a large pan over medium heat. Add the onion and sauté until soft and translucent, 3 to 5 minutes. Add the uncooked rice and stir until nicely coated with oil. Continue cooking, stirring continually, for about 2 minutes, then add the garlic.
• Continue to sauté until the rice is lightly toasted and golden in color, 3 to 4 minutes more. Be sure to stir continuously to prevent the garlic from browning. Remove from the heat and set aside to cool for about 10 minutes.
• Place the pork and beef in a large bowl. Add the salt, pepper, and the cooled onion-rice mixture. Using your hands, combine thoroughly, making sure that the seasonings and rice are evenly distributed throughout the meat.

Make the cabbage rolls:

• To roll the cabbage, place a leaf, inner side up on a towel. Place 1-1/2 to 2 tablespoons of the meat mixture at the bottom, center of the leaf (see photo above).
• Roll the cabbage leaf around the filling, using just enough pressure to make a firm roll without splitting the leaf (see photo above). Using a paring knife, trim away the extra cabbage on the sides, leaving about 3/4-inch of unfilled cabbage on either side for tucking in. Set aside the trimmings to be chopped and added to the cooking pot.
• Using your thumb and middle finger on either side of the roll, gently tuck the ends of the cabbage into the meat mixture, forming a dimple on each end (see photo above). Set the finished rolls aside as you work.

Prepare the sauce:

• Once you've used up all of the meat, take what's left of the cabbages along with the trimmed veins and ends, chop them roughly and place them in a very large bowl.
• Add the sauerkraut and, using your hands, mix well.
• Add the diced tomatoes, tomato paste and 1 cup of the tomato juice. Combine thoroughly.

Bake the cabbage rolls:

• Preheat the oven to 350°F. Coat a large pot or Dutch oven (7 to 8 quart - see notes) with nonstick spray. Place a 3/4-inch thick layer of the chopped cabbage-sauerkraut-tomato mixture in the bottom. Layer some cabbage rolls on top, keeping them 1/2-inch or so from the sides of the pot. It's fine for them to be close together.
• Add another, thinner layer of chopped cabbage, then more cabbage rolls, repeating as needed, finishing with a layer of chopped cabbage.
• Pour 2 more cups of tomato juice evenly over the rolls and around the edges of the pot, making sure all the rolls are moistened. It is not necessary for the rolls or chopped cabbage to be submerged in liquid.
• Lay the bacon strips over the top and cover tightly. Bake for 2 hours, checking midway through the cooking time to see if more tomato juice is needed to keep the rolls moist.
• After 2 hours, test for doneness by cutting one of the cabbage rolls in half and tasting to see if the rice is tender. If not, return the pot to the oven for an additional 30 minutes to 1 hour.