Melt the butter in a large skillet over medium heat

Add the mushrooms and minced garlic and cook for 15 - 20 minutes, until the mushrooms cook down and release their liquid and start to brown. There should be no liquid remaining

Cook the fettuccine to al dente according to the package directions

Once the mushrooms have cooked down, add the heavy cream, oregano, vegetable broth, salt, and parmesan cheese. Add the cooked fettuccine noodles and stir and toss over medium heat until the sauce is absorbed by the noodles. It will look like too much liquid at first, but use tongs to toss the noodles until they absorb most of the liquid

Serve immediately