In a dutch oven or deep heavy pot cook the garlic, the onions, and the carrot in the oil over moderately low heat, stirring, until the vegetables are softened. Add the russet potatoes, peeled and cut into 1-inch pieces, the broth, and 4 cups water, bring the liquid to a boil, and simmer the mixture, covered, for 10 to 15 minutes, or until the potatoes are tender. While the potatoes are cooking, in a skillet cook the sausage over moderate heat, stirring, until it is browned lightly and transfer it with a slotted spoon to paper towels to drain. With the slotted spoon transfer the cooked potatoes to a blender, add about 1 1/2 cups of the cooking liquid and purée the mixture until it is smooth. Stir the purée into the broth mixture, add the sausage, the kale, the red potatoes, cut into 1-inch pieces, and salt and pepper to taste, and simmer the soup, covered, for 10 minutes, or until the potatoes are tender.  Garnish with a teaspoon of creme friache or thick Greek style yogurt.