Kielbasa Kale Stew

Place the potatoes into a large stockpot, over medium high heat. Add butter and water, and bring to a boil. Cook potatoes until tender, about 20 minutes. Reserve the cooking liquid and mash potatoes in the pan until smooth. Return the potato water to the pot and stir in salt and pepper. Simmer for 20 minutes.
Stir in the fresh kale and sausage and simmer for another 30 minutes. Serve hot.