1. Cook bacon in a pan until crisp. Set aside.
2. Sautee shallots, garlic, and pepper flakes in the bacon fat until aromatic.
3. Add squash and stir for 2-3 minutes.
4. Add stock. Simmer until fork tender, adding more water as needed.
5. Transfer squash to a blender and process until smooth.
6. Bring squash puree back into the pan.
7. Blend in parmesan and a bit of pasta water to a smooth consistency.
8. Season with salt and pepper to taste.
9. Toss in cooked spaghetti.
10. Top with reserved bacon and chopped parsley.