Preheat your oven to 350F and boil some water. Place the cabbage leaves in a large bowl then pour the boiling water over the top. Allow the leaves to sit for 3-5 minutes before removing them. You want the leaves to have a structure to them but be soft enough to manipulate and roll. Set the leaves aside.
In a bowl mix together the mayonnaise, ketchup, garlic, lemon juice, sriracha, onion powder, salt, and pepper to create the thousand island dressing.
In a medium bowl mix together the pastrami, cheese, sauerkraut, and half of the Thousand Island Dressing.
Lay a cabbage leaf out on a cutting board. Spoon 1/8 of the meat mixture into the center of the leaf. Roll up like it’s a burrito, then place seam side down into a baking dish. Repeat this step with the rest of the leaves.
Spread the rest of the dressing across the top of the cabbage rolls, then place the baking dish into the oven and cook for 30 minutes.