Cook fettuccine according to package directions.

In the meantime, heat olive oil and butter in a large skillet.

Add onions and mushrooms; cook over medium heat until tender, stirring occasionally.

Stir in garlic and continue to cook for 1 minute.

In a small bowl whisk together flour and broth.

Add to skillet.

Stir in the milk and vegetables.

Season with salt and pepper, increase heat and bring mixture to a boil.

Continue to cook and stir for 1 minute or until sauce has thickened.

Decrease heat to medium-high and add turkey; cook for 3 to 4 minutes, stirring occasionally, until heated through.

Remove from heat.

Serve over prepared fettuccine.