Combine coconut milk, beef broth, portobello mushrooms, green bell pepper, onion, and sea salt in a 9x13-inch casserole dish; mix well. Add beef tips; stir until well-coated.
Bake in the preheated oven until beef is tender and sauce has thickened, about 1 hour.
Bring a large pot of lightly salted water to a boil. Cook linguine at a boil until tender yet firm to the bite, about 11 minutes; drain. Serve beef tips and sauce over pasta.
