Place butternut squash and chicken broth in a 4-qt instant pot. Season with salt and pepper to taste, lock lid into place, and close vent.
Cook butternut squash on high pressure 4 minutes, then quick-release steam and remove lid. Transfer butternut squash and any remaining liquid in instant pot to a food processor or blender and blend until smooth.
Return pureed butternut squash to instant pot and add pasta, garlic, cayenne, and water and stir well. Lock lid into place and close vent.
Cook pasta on high pressure 4 minutes, then quick-release steam and remove lid. Stir in cheeses, heavy cream, and milk until cheese is melted and mac and cheese is gooey. Season mac and cheese with salt and pepper to taste and serve warm. Enjoy!
Notes
Storing InstructionsStore mac and cheese in refrigerator up to 6 days.