In a large cooking pot, like a Dutch Oven, add the olive oil and heat over medium heat.
Add the diced onions and cook for about 3-5 minutes, until the onions are translucent.
Add the minced garlic and cook another 2 minutes, until fragrant.
Add the turkey, chicken broth, milk, mustard powder and cajun seasoning. Bring to a boil.
Add the pasta and give a good stir. Push down on the pasta to make sure it's all covered with the broth. Cover and turn down the heat to a simmer.
Simmer for 10-12 minutes, without lifting the lid.
After 10 minutes is up lift the lid and give a good stir. Check if the pasta is done. Cook a little longer if needed.
Once the pasta has cooked, at least to al dente, mix the cornstarch with a tablespoon of water. Pour into the pasta mixture and stir well.Once totally combined and the pot is bubbling again turn off the heat.
Add the grated cheese to the pot and stir well to combine and melt.
Notes
I used leftover turkey from Thanksgiving in this recipe, but you could just as easily brown 1lb of ground turkey and use that instead.