Step 1

Cut the tough center rib from the bottom of 16 cabbage leaves and set aside.

Step 2

Melt 2 tablespoons of the butter in a large skillet over medium heat. Add the onions, carrot and celery, season with salt and pepper and cook until softened and lightly golden brown, 5 to 7 minutes. Stir in the thyme and garlic and cook for another minute. Transfer to a large bowl and set aside.

Step 3

Place the skillet back over medium heat. Add the remaining tablespoon of butter and the mushrooms and season with salt and pepper. Cook, stirring frequently, until golden, about 5 minutes. Transfer the mushrooms into the bowl. Add the cooked rice, walnuts, dill, parsley, cumin and egg and stir well to combine.

Step 4

Whisk together the tomato sauce, cream and brown sugar in another bowl and set aside.

Step 5

If you’re prepping ahead and plan on freezing portions of two, grease four 6-by-8-inch foil pans or freezer-to-oven safe containers with nonstick cooking spray. If making a full batch immediately, grease a 9-by-12-inch baking dish. Pour two-thirds of the sauce into the pan(s) and spread across the bottom.

Step 6

Working with one cabbage leaf at a time, scoop about 1/2 cup of the rice filling onto the cabbage and tightly roll, tucking in the edges. Place the roll into the prepared pan(s), seam side down, and continue until all the cabbage and filling is used. Pour the remaining sauce over the cabbage rolls. If making ahead, cover and store the rolls in the fridge for up to 3 days or wrap the pans in plastic or freezer bags and freeze for up to 3 months.

Step 7

To cook the rolls, heat your oven to 400 degrees F. Cover with foil and cook until heated through, 30 minutes from fresh or about 1 hour from frozen. Remove the foil and cook for an additional 10 minutes or until the sauce on top is a bit jammy.

Step 8

Heat the oil in a large pot over medium heat. Add the onions, season with salt and pepper and cook until softened and lightly golden brown, about 8 minutes. Stir in the cherry tomatoes and garlic and cook until the tomatoes begin to break down, 5 to 7 minutes. Deglaze the pan with the wine if using and cook down until the wine is reduced by about half, 1 to 2 minutes.

Step 9

Carefully add the canned tomatoes along with the Parmigiano-Reggiano rinds and bring to a simmer. Turn the heat down to low and place an off-kilter lid on top to reduce splatter. Simmer for at least 15 minutes for a bright sauce and for up to 1 hour for a deeper, more rich sauce, stirring occasionally.

Step 10

Remove the Parmigiano-Reggiano rinds and season to taste with more salt and pepper and some sugar if needed. Stir in the basil and parsley, remove from the heat and set aside to cool to room temperature.

Step 11

Divide the sauce into four heavy-duty freezer bags, seal and lay flat on a sheet pan. Place in the freezer and freeze until solid. Stack the bags for easy storage and keep in the freezer for up to 3 months. To use, defrost in the fridge overnight or simply remove from the bag and heat in the microwave or over low heat.