In a large pot of heavily salted boiling water, cook the pasta until al dente per package directions. Before draining, reserve 1 cup pasta water and set aside.
In a large skillet on medium heat, add the pancetta and butternut squash. Cook, stirring occasionally until butternut squash can easily be pierced with a fork, about 10 minutes. (Sometimes I need to add a bit of water to the pan to help the butternut squash cook through)
Add olive oil, red pepper flakes, pepper, garlic, and kale to skillet. Stir and cook until fragrant, around 1 minute.
Toss the drained pasta into the skillet. Then, toss in the parmesan. Add the pasta water, a little at a time, and mix until parmesan completely coating pasta. You may not need the whole cup of reserved pasta water.
Salt to taste, remove from heat, and serve!