Winter Root Casserole

9 Tbls butter
1 lb. onion, halved and sliced
2 cloves garlic, minced
1 lb. potatoes, cut in half and thinly sliced
1 lb. carrots, peeled and thinly sliced
1 lb. parsnips, peeled and thinly sliced
3 Tbls white flour
2 ½ cups milk
1 ½ tsp salt
¼ tsp ground black pepper
¼ tsp ground nutmeg
1 cup grated cheese

Preheat oven to 375. Heat skillet over medium heat. Add 6 tbls butter, onions, and garlic and gently sauté for 15 minutes, stirring. In large baking dish or casserole, combine sliced root vegetables with cooked onions. Bake until tender, about 45 minutes to 1 hour. Meanwhile, heat remaining 3 Tbls butter over medium heat in sauce pan. When warm add flour and stir one minute. Then, dribble in milk while constantly whisking. Bring milk mixture to a boil while stirring. Then turn down heat and simmer 5 minutes until sauce has thickened, stirring. Remove from heat and add salt, pepper, and nutmeg. Add sauce to roasted vegetables and mix, topping with grated cheese. Bake 15 minutes until bubbly. Serves 6-8.