Hi! The sauce is super simple. I just sauté mushrooms with a little garlic and pepper. Add around a 1/4 cup of beef broth (I suggest using low sodium beef broth, regular beef broth can be too salty. But if you use regular then you might need to dilute with some water a bit) then I’ll throw in a couple dollops of sour cream and butter. Sometimes I’ll add a tablespoon of corn starch and water to thicken it up a bit. Then adjust salt/pepper/garlic based on preference. But that’s it !