On medium high heat, warm up a skillet. Add butter and allow it to melt. Add the mushrooms, cook for about 3-5 minutes. Then add the onions and cook until it's translucent & soft.
Remove the mushroom & onion mixture. Set aside for later.
Brown and break up the ground beef. Cook for 3-5 minutes or until it's no longer pink.
Add brandy, beef broth, and Worcestershire sauce.
Add the mushroom mixture back with the meat, even the liquid. Sprinkle nutmeg on top. Stir and combine all the ingredients.
Add cream cheese and stir until it's melted. Then add in sour cream. Cook for a few more minutes until the sauce is thick and creamy.
Season with salt and pepper. Taste and adjust according to your liking. Sprinkle some parsley on top for a pop of color.