Heat a large heavy-duty pot over medium-high heat. Once the pot has heated through, add the sausage, which you removed from the casing. Using a wooden spoon, begin to break up the sausage and allow it to cook, stirring occasionally, until it has fully browned. Remove the crisped sausage from the pot and transfer it to a plate or bowl. Set aside.

Lower the heat to medium, add the butter or oil and throw in the onions and garlic. Stir, scraping down the bottom of the pot picking up the browned bits of sausage with the back of a wooden spoon, and cook until soft and translucent about 3 to 5 minutes. Season with salt, pepper, and crushed red pepper flakes, if using. Continue to sauté until the onions have caramelized. Add the chopped kale in batches, allowing it to wilt down as it cooks. It might seem like a lot of kale but it will cook down, just like spinach! Add the nutmeg and stir. Cook the kale for another 3 minutes until it has turned bright green and completely wilted down. Throw in the sliced potatoes and cooked sausage.

Pour in the chicken stock or broth and bring it up to a boil. Lower the heat and allow the soup to simmer until the potatoes are cooked tender and soft. Taste the soup for seasoning, at this point you may add more salt, pepper or red pepper flakes, if desired. Once the potatoes are fully cooked, stir in the heavy cream. Serve right away with some bread on the side. Enjoy!