Heat olive oil in a large skillet over medium heat.
Add sliced mushrooms and cook until softened and browned, about 8-10 minutes.
Add minced garlic and cook for another minute until fragrant.
Pour in heavy cream and bring to a simmer. Reduce heat and simmer for 5 minutes, or until the sauce has slightly thickened.
Stir in grated Parmesan cheese, salt, and pepper. Adjust seasoning to taste.
Serve immediately over cooked ravioli.
Notes
Garnish with fresh parsley or more Parmesan cheese, if desired. For a richer flavor, add a splash of white wine to the sauce while cooking the mushrooms.