In a Dutch oven or stock pot, melt butter over medium heat.
Add in the onions and cook until they start to color.
Add in garlic and spices, sautéing and giving the spices the aroma.
In a separate dish, cook the chicken until it reaches 165°. Either stovetop or baked works well.
Add broth to the onion/butter/spice mixture and stir well. Bring to a simmer and cook for 20 minutes.
While that is heating up, shred the chicken and add to the soup mixture.
After chicken has been added, bring a pot of water to a rolling boil and cook the pasta until al dente. Drain - do not rinse.
Whisk together cream and cornstarch in a bowl.
Combine all ingredients at this point - cream/cornstarch mixture, pasta, chicken/broth, as well as spinach. Heat back up to a simmer.
Serve into bowls and top with shredded cheese.