Candy Onion Gratin

3 cups chopped candy onions
5 tablespoons butter
4 tbsp milk
1/2 tsp salt
1/8 tsp (or a pinch) nutmeg
1/2 cup grated Emmentaler cheese
1/2 cup plain panko bread crumbs


Melt butter in a large saucepan. Add onions, and cook covered over medium high heat for about 20 minutes, or until soft, stirring frequently. If onions begin to stick to the bottom of the pan, add milk 1 tbsp at a time.
Preheat broiler.
Add salt, nutmeg, and remaining milk to onions, and continue to cook until onions are very soft and creamy, but there is no liquid left in the bottom of the pan. Transfer mixture to casserole dish. Top with grated Emmentaler and panko. Place under the broiler until golden brown, probably not more than 5 minutes (but this varies with each oven).
Serve hot.