Prepare all ingredients by slicing the beef, dicing the onion, mincing the garlic, and slicing the mushrooms.
In a large skillet, heat the olive oil over medium-high heat. Add the sliced beef and cook for 3-4 minutes until browned. Remove and set aside.
In the same skillet, add the diced onion and cook for 3 minutes until soft. Add minced garlic and sliced mushrooms, cooking for 5 minutes until tender. Return beef to skillet, add beef broth, Worcestershire sauce, and Dijon mustard. Stir and simmer for 5 minutes.
Reduce heat to low and stir in coconut milk. Cook for an additional 2-3 minutes until heated through. Season with salt and pepper to taste.
Serve over cooked gluten-free pasta and garnish with chopped parsley.