Sauté yellow onion and mushrooms in 1 tbsp of olive oil over medium-high heat for 5–7 minutes. Add garlic at the very end to prevent burning.
Step three:
Stir in flour until absorbed by the oil and mushrooms. Add chicken stock and Marsala wine, letting it thicken for 5–10 minutes. Season with salt and add heavy cream, heating until warm.
Serve:
Add the cooked ravioli to the sauce, gently folding them in to coat. Add parmesan cheese and serve immidietly