Add the sausage, all of the seasonings, and half of the garlic to a bowl and stir to combine. Let this rest for 20-30 minutes to let the flavors blend. You could even do this earlier in the day.
Cook the pasta according to the directions on the package and reserve 1/2 cup of the cooking water before draining it. Drain the pasta and set aside.
Heat the olive oil in a large pan over medium-high heat.
Add the sausage and cook until it's no longer pink, about 4-5 minutes. Break the sausage up with your spoon as it cooks.
Turn the heat down to medium, add the garlic and onion, and cook for another 3 to 4 minutes or until the onion is softened. Watch this carefully so the garlic doesn't burn.
While the onions and garlic are cooking, roughly chop the greens and remove any large stems.
Add the butter, reserved pasta water, and all of the greens to the pan and toss to combine. Cook this for 1 - 2 minutes or until the greens are just wilted.
Turn the heat down to low, add the pasta and toss to combine.
Remove the pan from the heat and add the Parmesan a little at a time, tossing in between each addition.
Taste and adjust the salt and pepper to your liking before serving.
Serve with extra Parmesan cheese, if desired!