Step 1

Cook pasta according to package directions.

Step 2

Meanwhile, heat oil in a large skillet over medium-high heat. Add onion and cook until fragrant and starting to soften, about 2 minutes. Add garlic and mushrooms and continue cooking, stirring frequently, until the mushrooms release their liquid, 5 to 7 minutes.

Step 3

Stir in flour and cook, stirring, until it is well absorbed, about one minute. Add wine, broth and mustard; stir and scrape up any browned bits. Reduce heat to medium and continue to cook, gently stirring, until the sauce thickens, 3 to 5 minutes. Remove from heat. Stir in sour cream, salt and pepper.

Step 4

Drain the pasta and add to the sauce, tossing it all together. Sprinkle with parsley, if desired.