Self-Crusting Quiche

Too lazy to roll out crusts and living too far from the store to buy them, I make:

Self-Crusting Quiche

1 medium onion, chopped
2 Tablespoons of unsalted butter, divided
3 cups vegetables such as bell peppers, chopped broccoli, or mushrooms, cut into pieces
1 cup shredded good-quality Parmesan or Asiago cheese
1-1/2 cups milk (not skim)
3/4 cup biscuit mix (such as Bisquick)
3 eggs
salt and pepper to taste
fresh herbs to taste

1. Preheat oven to 400 degrees. Grease or spray a 10-inch quiche pan or pie pan.
2. Saute onions in one tablespoon of  of butter until they begin to brown. Add the other tablespoon of butter, the vegetables, and saute until the vegetables soften and any liquid has evaporated.
3. Cover the bottom of the greased pan with the vegetables. Beat all the other ingredients together until they're smooth. Pour over the vegetables. Bake 30 to 35 minutes. Cool 5 to 10 minutes and serve. Also tastes good at room temperature.