If you haven’t cooked your butternut squash ahead of time, preheat your oven to 400 degrees. Place the cut squash on a baking tray, flesh side down, and roast until it is fork tender, about 40-45 minutes. Allow it to cool and then scoop the flesh into a bowl and set aside.
Reduce the heat of the oven t0 375 degrees (or preheat if your squash was already cooked).
Heat one tablespoon of butter in a medium skillet over medium heat. Add the onion and cook until soft, about 5 minutes. Add the kale leaves and cook until they are bright green and tender, about 2-3 minutes. Stir in the butternut squash. If there are any lumps in the squash, use the back of your spoon to mash them until you have a smooth mixture.
In a medium sauce pan, heat the remaining 4 tablespoons butter with the garlic over medium low heat until the garlic is soft, about 2 minutes. Stir in the flour and cook for 3 minutes. Whisk in the milk until smooth. Bring to a simmer, and cook until it thickens, about 10 minutes, whisking frequently. Stir in the butternut squash and kale mixture. Taste and season with salt and pepper.
Pour 1 cup of the sauce into the bottom of a 9X13 inch baking dish. Top with 3 noodles and then break a noodle into pieces and use 1/2 to 1/3 of it to cover the remaining space (2 of the 9 noodles will be broken to cover the small end space in each layer). Top the noodles with 1/3 of the remaining sauce and sprinkle with 1/4 cup parmesan cheese. Add another layer of noodles. Add 1/3 of the sauce and top with 1/4 cup parmesan cheese. Add a last layer of noodles. Top with the remaining sauce and 1/4 cup + 2 tablespoons parmesan cheese.
Cover with foil and bake in the 375 degree oven for 30 minutes. Remove the foil and bake an additional 10 minutes. Allow to rest 5-10 minutes before serving. Enjoy!