Add olive oil to an oven-safe skillet over medium high heat until just smoking. Add sausage and onions and cook until lightly browned, about 4 minutes. Add garlic and cook until fragrant, about 30 seconds.

Add broth, tomatoes, half and half, pasta, salt and pepper and stir. You may want to add a little water or other liquid to so that you can see it level with the pasta.

Bring to a boil, cover skillet, and reduce heat to medium-low.

I set the timer for 3 minutes and check, with the half and half this can start to scorch quickly, so turn it down if it still is bubbling.

Set the timer for 5 minutes two more times - check and stir the pasta each time. It should be done in about 15 minutes.

Remove skillet from heat and stir in cheese. Top with with scallions (optional).