Place 3.5-5 qt skillet on medium high heat, add bacon, cook until browned.
Add onions, cook for 5 minutes, add garlic and cook for an additional 2-3 minutes.
Add red peppers, stir to combine.
Meanwhile cook pasta according to package Al dente instructions, remembering to reserve 1 cup pasta water.
Then, scoop squash from peel into blender, pour in any remaining water as well.
Add cream and blend just until smooth, 10-30 seconds.
Reduce skillet to medium, add squash sauce.
Pour pasta liquid into blender container, gently swirl to gather squash mixture, then pour half into skillet.
Stir to combine.
Add pasta, spinach, and cheese.
Stir to combine.
Use additional pasta water as needed get preferred sauce thickness.
Serve immediately.
Option to top with additional shredded Parmesan and red pepper flakes.