Saute the onions with the bay leaf and thyme in the butter and oil. Season with salt and pepper and let them cook about 20 minutes until they are caramelized and golden. Remove the bay leaf and cool the onions. In a bowl whisk the eggs, half and half, sour cream and onion soup mix until well combined and season with salt and pepper to taste. Pile the onions on the bottom of the pie crust and top with egg mixture. Sprinkle the cheese on top and bake for about 40-45 minutes in a 350 degree oven until the center is set and it is golden brown.