Bring a large pot of salted water to a boil. Cook your pasta according to the package instructions. Reserve 1 cup of the pasta water (you may not need all of it, but it's best to have extra!) Drain your pasta, and set aside.
Pull the kale leaves off their stems, and roughly chop the leaves. Wash the leaves well, drain, and set aside.
Heat a large skillet over medium heat. Add oil and garlic, and sauté for about 1 minute, or until the garlic is fragrant (but not browned!!)
Add the kale to the skillet, along with a pinch of salt and 1/4 cup of the pasta water. Cover your skillet and cook on medium heat until the kale is wilted (about 2 to 4 minutes).
Uncover, turn off the heat, and add red pepper flakes and grated Parmesan. Toss together until the cheese is melted and everything is incorporated. Add your cooked pasta and toss again to combine. (Optional) Top with more cheese and red pepper flakes!