In a skillet, heat a drizzle of olive oil over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
Add minced garlic and continue to sauté for an additional minute until fragrant.
In the same skillet, add the Italian sausage. Break it apart with a spatula and cook until browned and cooked through, about 5-7 minutes. Drain any excess fat.
Transfer the cooked sausage, onions, and garlic to the slow cooker.
Add the thinly sliced potatoes and pour in the chicken broth. Stir in the Italian seasoning, salt, and pepper.
Cover the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours until the potatoes are tender.
Once the potatoes are cooked, stir in the chopped kale and heavy cream. Allow to cook for an additional 15-20 minutes until the kale is wilted and the soup is heated through.
Taste and adjust seasoning as necessary, adding red pepper flakes for a kick if desired.
Notes
Serve in deep bowls, garnished with extra Italian seasoning and cream. Fresh crusty bread pairs beautifully on the side.