In a skillet, set heat to medium and add olive oil and butter

Add mushrooms and onions, stir occasionally for about 5 min. Add salt and pepper

Turn heat to medium high, add scotch. Stir. Once the scotch has been just about soaked up by the mushrooms and onions, turn heat back to medium

Add heavy cream. Stir. It'll start to bubble and thicken. Once that happens, turn heat to low and simmer for 5 min.

That's it! Top with a bit of fresh parsley.