Brown the pork sausage on med-high heat for approximately 7 to 9 minutes. Add white onion and cook for a couple minutes.Remove pork sausage and onion mixture from pan using a slotted spoon to reserve as much of the fat from the sausage in the pan. Set sausage and onion aside for later use.
Add butter to the pan with residual fat from the sausage. Stir in flour and cook for a couple minutes. Then slowly pour in half-n-half. Be sure to continually stir as you are adding the half-n-half, otherwise your sauce may end up lumpy. Cook for a few minutes until sauce thickens.
Roll out pizza dough as directed per the package. Evenly spread 1/2 a cup to 3/4 of a cup of the sauce on the dough. Evenly spread/sprinkle mozzarella cheese, sausage and onion mixture on dough.
Bake in the oven for 15 minutes.
While pizza bakes, clean kale and tear into bite size pieces. Dress kale with Olive Oil. I usually add the kale to a zip-lock bag and shake it up.
Remove the pizza from the oven and top with kale. Keep in mind that the kale will shrink so it will look like a lot of kale. Sprinkle with garlic salt. Place pizza back into the oven for 5 to 7 minutes. You want the kale to be nice and crisp and still green, not browned. Browned is burnt, so watch it carefully.
Remove the pizza from the oven and allow it to cool for at least 5 minutes before cutting.