Put the cored cabbage in a large pot. Cover it with water and add 2 tablespoons salt, then bring to a boil. As the cabbage cooks, the outer leaves will begin to detach themselves. When they’re soft, carefully remove them with tongs, place the leaves on a plate or in a bowl, and wait for the next outer leaves to detach. Repeat this until all the leaves have fallen off. This will take some time, so be patient. Save any broken, torn, or small leaves, you’ll use the whole cabbage.

In a large pan, on medium high heat add olive oil and heat until shiny. Add the onion and cook until softened, about 3 minutes. Add chopped mushrooms and 1/2 tsp salt and cook until the mushrooms have released most, if not all, of their liquid. About 7-8 minutes. Remove from heat.

In a large bowl, using your hands, mix together, sautéed onion and mushrooms, 1 lb beyond beef ground beef, 2 cups rice, 1 egg, 1 1/2 tsp salt, black pepper, dried fennel, celery seed, garlic powder and tamari.

Preheat the oven to 350F. Take any exterior cabbage leaves, broken leaves, or leaves too small to roll and roughly chop them so they’re bite sized. Cover the bottom of a large dutch oven in a layer with all the sour kraut and the chopped extra cabbage. Working one at a time, use a knife to trim and flatten the stem of the cabbage leaf, fill each leaf with about 1/4-1/2 cup of the filling depending on the size of the leaf, and roll up tightly being careful not to rip the leaves. Place the rolls snuggly up against each other in the pot. When you cover the bottom layer, start a new layer of rolls right on top.

In a large bowl, stir together 2 cans of crushed tomatoes, 1 tsp kosher salt and brown sugar. Pour the tomato mixture over the cabbage rolls. Cover and bake for 90 minutes or until internal temperature of the rolls reaches 160F.