Heat the olive oil over medium high heat. Add the onions, garlic, and mushrooms to the pan. Cook for 4-5 minutes until mushrooms are becoming tender. Stir often so the garlic doesn't burn. Add the grill seasoning.
Add the broth and bring it to a boil. Turn it down to a simmer. Add the pasta and simmer for 10-15 minutes until the pasta is tender and has absorbed most of the liquid. Stir as needed, especially as the liquid is absorbed more. Add extra liquid if needed. Keep the lid closed when you aren't stirring the pasta.