Boil a large, salted pot of water for the pasta. Cook pasta according to package instructions.

Add the butter and oil to a skillet over medium-high heat. Once it's hot, add the garlic, Dijon mustard, flour, lemon juice, Italian seasoning, and chicken broth to the pan. Return the pan to the heat. Stir until the mixture is nice and smooth, and let it bubble for a minute or so.

Add in the cream and let it simmer for a couple of minutes.

Add the shrimp and mushrooms to the pan. Cook for 5 minutes or until the shrimp are cooked through and the sauce is thickened to your liking. Taste and season with salt & pepper as needed.

Drain the pasta and toss it with the sauce (add a little pasta water if you wish to thin the sauce). Serve with grated parmesan if you wish.