Slice the mushrooms and chop the onion and garlic.
Start cooking the tortellini according to package instructions.
Heat the olive oil in a sauce pan and fry the mushrooms until they are brown and tender (about 5 minutes). Add salt & pepper.
Add the onions and fry for a few minutes until soft. Then, add the garlic and fry for 30 seconds.
Reduce the heat and add the cooking cream, Parmesan cheese, and spinach. Stir carefully until the spinach is wilted (about 3 minutes). If the sauce is too thick, add a bit of water from the tortellini.
Add the tortellini and stir carefully to cover with the sauce. Done!