In a Dutch oven or wide bottom sauce pan over medium high heat, add in olive oil, onion, garlic and a pinch of salt. Proceed to sweat the onions and garlic for about 5 minutes or until all the moisture has been cooked out and the onions are translucent and soft.
Add in the mushrooms, a pinch of salt and a little more oil if needed. Cook the mushrooms for about 5 minutes, stirring constantly until they have released their liquid and have shrunk slightly.
Stir in thyme and cook for another 6-7 minutes until the mushrooms have lightly browned.
Deglaze the pan with the marsala. Reduce until it is nearly dry.
Add in cream and a splash water. Simmer for 5 minutes until the sauce coats the back of a spoon.
Bring a pot of water to a boil and add in a strong pinch of salt. Cook the ravioli in the boiling water for 3-4 minutes, or until they are all floating. Using a slotted spoon or spider, remove the ravioli from the water and begin tossing them in the sauce gently. You may need to add a splash of pasta water to adjust the consistency of the sauce. The sauce should be saucy but not watery.
Taste the sauce and pasta and adjust the seasoning and consistency if necessary.
Serve up the ravioli and top with more parmesan.