Wipe the mushrooms clean on paper towels.
Heat the olive oil and butter in a 12-inch skillet.
Add the garlic and mushrooms.
Cook over a medium heat for 5 minutes or until the mushrooms are soft.
Turn the heat down and stir in the cream cheese.
Cook for a few minutes, then turn the heat right down to low.
Stir in the cream, parmesan, oregano, salt, and black pepper.
Simmer for about 5 minutes, stirring frequently.
Take the mushrooms off the heat and sprinkle with parsley.
Serve right away.