9 tbsp. butter, softened
3 lbs. kale
1/2 lb. lean bacon, coarsely diced
1/2 c. beef or chicken stock, fresh or canned
2 tsp. salt
1/4 tsp. ground nutmeg
9 med.-sized boiling potatoes (about 3 lbs.), peeled and cut into 1/2-inch cubes
1/2 to 3/4 c. milk
Freshly ground black pepper
2 egg yolks

With a pastry brush, coat the bottom and sides of an 8x10-inch baking dish with 1 tablespoon of softened butter. Set the dish aside.

Wash the kale thoroughly under cold running water. With a small, sharp knife, cut away the ends and the tough stems as well as any bruised or yellowed leaves. Drop the kale into enough lightly salted boiling water to cover it completely and boil briskly for 10 minutes. Drain thoroughly in a colander, and with the back of a spoon press it firmly to remove any excess liquid; then chop the kale coarsely.

In a heavy 4 to 5-quart saucepan, cook the bacon over moderate heat until it is crisp and brown. Add the kale, turning it about with a large spoon until the leaves are coated with the fat. Then stir in the stock, 1 teaspoon of the salt and nutmeg, and bring to a boil over high heat. Reduce the heat to low and simmer uncovered, stirring occasionally, for 20 minutes.

Meanwhile preheat the oven to 400 degrees. Drop the potatoes into enough lightly salted boiling water to cover them completely, and boil them briskly, uncovered, until they are tender but not falling apart.

Drain thoroughly, return them to the pan and shake them over low heat for 2-3 minutes until they are dry. Then force the potatoes through a food mill or ricer set over a bowl. A tablespoon at a time, beat 5 tablespoons of softened butter into the potatoes and then the milk a few tablespoons at a time, using as much of the milk as you need to make a puree thick enough to hold its shape in a spoon. Beat in the remaining teaspoon of salt, a few grindlings of black pepper and the egg yolks, one at a time. Taste for seasoning.

Spread the cooked kale evenly over the bottom of the prepared baking dish, smooth the potatoes over it and dot the top with the remaining 2 tablespoons of butter cut into small pieces. Bake in the middle of the oven for 20 minutes, or until the surface of the potatoes is golden brown. Serve at once, directly from the baking dish.