Heat a skillet over medium and add in the butter, then sauté the mushrooms, onions, salt and pepper for a few minutes, until you have some good color. All the brown bits on the bottom of the pan, that's exactly what you want! This is important, because it will give a lot of flavor to the sauce! Add in the garlic for about 20 seconds, careful not to burn it.
Deglaze the pan with the white wine, scraping up the brown bits of flavor. Add in the beef or chicken stock, roast beef, Worcestershire sauce and mascarpone cheese.
Simmer for 5-7 minutes, then stir in the Xanthan Gum and sour cream, then turn off the heat, once it has melted. I only used 1/4 teaspoon of the Xanthan Gum and it was the perfect amount.
That's it, you're done! I told you it was quick and easy! Serve over zucchini noodles, cauliflower rice, mashed cauliflower or shirataki noodles and enjoy!
Store leftovers in the fridge for a few days or freeze.
*Macros are for the beef stroganoff. Be sure to adjust them according to what you serve your's with.