Carefully remove core from head of cabbage and discard discolored outer leaves.
Fill a large-size pot about halfway with water and bring to a boil. Place the whole head of cabbage into the water (it should be submerged).
Boil until it is al dente and the outer leaves can be peeled off without breaking, 10 to 15 minutes. Set aside to cool.
In a large-size bowl, combine the ground beef, cauliflower rice, parsley, onion powder, salt, garlic powder, and pepper. Use your hands to mix well.
For this recipe or any similar (meatballs, meatloaf, etc) to check your mixture for correct seasoning, cook a small patty to sample.
Gently peel the outer 8 leaves off the boiled head of cabbage and reserve for the cabbage rolls. With a sharp knife, shave off any thick veins from the outside of the reserved cabbage leaves. Quarter the remaining head of cabbage, cut out the core from each quarter, and place in a Dutch oven or 2-quart (2 L) casserole dish.
Lay a cabbage leaf out in front of you so that where is was connected at the core is toward you and it is curling up. Place one-eighth of the meat mixture about 2 inches (5 cm) from the edge closest to you and shape the meat into a 3-inch (7.5 cm)-wide log.
Fold the 2 inches (5 cm) closest to you over the top of the meat and roll it so that the edge is underneath the meat.
Next, fold the right side of the leaf over the meat (you can trim the sides if there is more than 2 to 3 inches [5 to 7.5 cm] of cabbage).
Repeat with the left side.
Roll the meat forward, toward the farthest edge.
Place the cabbage rolls, seam-side down, in the Dutch oven, casserole dish, crock pot/slow cooker or pressure cooker, along with the cabbage quarters.
Pour the tomatoes and juice over the top, and sprinkle with additional salt and pepper.
Bake: Cover and bake at 350 for 2 hours, or until the rolls are so tender you don’t need a knife to cut them.
Crock-Pot/Slow Cooker: cook on low for 6-8 hours
Pressure Cooker: cook under high or standard pressure for 20 minutes. Allow to naturally depressurize.