I adapted this recipe from this post at Former Chef’s blog, which was in turn adapted from Giuliano Hazan’s 30 Minute Pasta book. It’s a really fast, really good meal, especially if you cut up the squash in the morning so it’s ready to go a dinner time.
Rotini with Butternut Squash and Bacon
(Adapted from Former Chef and Giuliano Hazan’s Thirty Minute Pasta
1 yellow onion, diced 
3 Tbsp. butter
3 oz Pancetta, cut into 1/4″ pieces (could use bacon)
1 medium butternut squash, diced into 1/2″ cubes
1 cup water
salt and pepper to taste
1 lb pasta
3 oz Grated parmesan cheese
Boil water for the pasta. Add the butter to a large saute pan and add the diced onion. Cook over medium heat until golden brown. Add the panceta and cook until it starts to crisp, about 2-3 minutes.
Add the squash and season with salt and pepper. Add the water, stir and cover with a lid for 10 minutes until the squash is soft. Check after 5 minutes and add more water in 1/4 cup increments if it’s drying out, until the squash is soft enough to mash with the back of a spoon.
Cook pasta and reserve about 1/2 cup of pasta water before draining.
Add 1/4 cup of the reserved pasta water to the sauce, smashing the butternut squash with the back of a large spoon. If it seems too thick, add the other 1/4 cup. Toss the sauce with the cooked pasta and the grated cheese and serve.