additional 1/4 cup water, broth, milk or cream(optional)
Pasta: Cook the pasta according to package directions. Set aside and toss with a little oil to prevent sticking.
Mushrooms: Melt 2 tablespoons of butter over medium high heat. Add one clove of the garlic and saute for a minute until fragrant. Add the mushrooms and sauté for 5-10 minutes, until golden brown and softened. Set aside.
Sauce: Add the remaining 2 tablespoons of butter to the pan and melt again over medium high heat. Add the garlic and saute for a minute until fragrant. Add the flour and herbes de provence. Stir fry for a minute to cook out the flour taste. Add the milk slowly, whisking to incorporate. Let the mixture simmer until thickened. Season with salt and pepper.
Assemble: Toss the sauce, pasta, and mushrooms together. Add the olive oil and water as needed to keep the sauce from getting too thick. Stir in the parsley just before serving