Add pasta to boiling water and cook as directed on the package. Drain in a colander and return to pot away from heat.
In a sauce pan over medium high heat, add butter, onion powder and garlic powder. Once melted whisk in flour. Let cook for two minutes then whisk in milk and let cook for two minutes then whisk in seasonings and cook another two minutes. Whisk in heavy cream and cook another two minutes. Then add in cheese, a handful at a time, whisking until it's melted in.
Add cheese sauce and spinach to pasta. and stir to thoroughly combine. Let sit for about 5 minutes before serving.
NOTE: If you like the spinach to be cooked more than just wilted, add it to the cooking pasta in the last 3 minutes of cook time.
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