Get 1 tbsp. of olive oil in a large pot or Dutch oven heating on medium-high heat. Once its hot, add the sausage and cook until browned, breaking it up as you go. Remove it to a towel lined plate and cover it with foil. Set it aside. Then add the additional oil and the butter to the pot. Once it's hot and the butter has melted, add the onions with a pinch of salt.
Cook the onions until translucent, then add the garlic and cook another minute or two, until fragrant. Then stir in the flour and cook for another minute or two. Next stir in the broth about a cup at a time, making sure the flour mixture is smoothly mixed in and there are no lumps, then stir in the cream, the salt and pepper. Let this come up to a low boil.
Once at a boil, return the sausage to the pot and stir in the potatoes. Lower the heat a bit. Let this simmer until the potatoes are fork tender, then stir in the kale and cook just a couple of minutes more, until the kale has wilted. Taste the soup to check if it needs more seasoning. Then remove from the heat and serve.
