1. Heat butter in a 2 litre souffle dish, uncovered, at 100% for 2 minutes. Add curry powder, onions, and cabbage and stir to coat.
2. Cover tightly with plastic wrap and cook at 100% for 4 minutes. Remove from oven and stir.
3. Mound cabbage mixture in center of dish and arrange salmon around cabbage. Sprinkle salt, pepper, and lemon juice over all. Cover tightly with plastic wrap and cook at 100% for 8 minutes.
4. Remove from oven. Uncover and stir. Re-cover dish and let stand for 3 minutes before serving.