Mash the potatoes and stir in the cream, butter, and cheese as described above. In a large Dutch oven, combine the potatoes, parmesan rind (if using), heavy cream, milk, garlic, and sage.

Leave the fat in the skillet and transfer the kielbasa to a Dutch ... leaves from the tough stems and ribs, and then chop the leaves. Add them to the sausage and leeks along with the potatoes ...