Prepare the cabbage. Cut out the tough core of the cabbage and place the head in a large pot of boiling salted water. Cook for 5–8 minutes until the outer leaves soften, then carefully peel off 12–14 intact leaves. Continue boiling until you have enough soft leaves; drain and reserve some of the cooking water.
Cook the rice. In a small saucepan combine the rice and milk. Simmer gently for about 20 minutes until the grains are tender and most of the milk is absorbed. Let cool.
Make the filling. In a skillet melt a dab of butter and sauté the chopped onion until translucent but not browned. In a large bowl mix the ground beef, ground pork, egg, cooked rice, cream, salt, white pepper and allspice/marjoram until you have a smooth mixture. If the mixture feels too thick, stir in a few spoonfuls of the reserved cabbage water.
Assemble the rolls. Lay a cabbage leaf flat with the rib side down. Place a generous tablespoon of filling near the stem end. Fold the sides over the filling, then roll up tightly. Repeat with the remaining leaves and filling.
Brown the rolls. Preheat the oven to 200 °C (400 °F). Melt the butter in a large frying pan over medium heat and brown the rolls on all sides. Transfer the seared rolls seam‑side down to a greased baking dish. Deglaze the frying pan with a splash of water or broth, scraping up browned bits, and reserve this liquid
Bake. Drizzle the syrup over the cabbage rolls. Pour the reserved deglazing liquid and about 200 ml of beef broth around the rolls. Bake for 30–40 minutes, basting occasionally with the pan liquid or reserved cabbage water. Cover the dish with foil if the rolls are browning too quickly. The syrup will caramelise the leaves and give them a golden sheen.
Make the gravy. While the rolls bake, sauté the chopped onion and carrot in butter until golden. Add the broth and cream; simmer until thickened. Season with soy sauce, salt and pepper. For extra flavour, add a few tablespoons of the pan juices from the baked rolls. Strain the sauce before serving for a silky texture.
Serve. Arrange the baked cabbage rolls on a platter, pour over some gravy and serve with boiled or mashed potatoes and a generous spoonful of lingonberry jam or purée. Leftovers reheat beautifully and can also be frozen.