Eggs Baked in Mushroom Sauce

It seems this dish could be served for any meal of the day but it is suggested for breakfast.  Dee had it at a friends house during a morning bridge party.  Start by cooking 1 lb. sliced mushrooms in 2-3T butter.  Remove the mushrooms from the pan and set aside.  Add 3T flour to the pan and stir until smooth.   Combine 2C whipping cream, 1 egg yolk, slightly beaten, and 1T finly chopped onion.  Stir the mixture and heat gently until it is smooth and bubbly.  Return the mushrooms to the pan and stir until heated.  Pour the mixture into a greased 13"x9" oven proof dish.  Carefully crack 8 eggs into the mushroom mix, spacing them evenly over the top.  Place the dish in a 350 degree oven for about 15 min, or until the eggs are cooked to your liking.  Place an egg and some of the mushroom sauce on a toasted muffin.  We served them with some sliced oranges dusted with cinnamon.