In baking dish, cook sausages at 400° until browned, 25 minutes. Place potatoes in bowl with 3/4 cup water, cover and microwave on high, until tender, about 12 minutes; drain. In large skillet with a lid, cook kale, leek and thyme in butter over medium until tender, 2 minutes. Add milk. Cover; bring to a simmer. Add potatoes; mash and season. Top with sausages.