SWISS CHARD AND SWEET POTATO GRATIN

Steps:

• Prep greens: Cook onion in 2 Tbsp butter in a wide 8-qt heavy pot over moderately low heat, stirring, until softened. Add chard stems, pinch of nutmeg, and salt and pepper to taste and cook, stirring, til vegetables are tender but not browned, about 8 minutes. Increase heat to moderately high & add chard leaves by large handfuls, stirring, until all greens are wilted. Season with salt and pepper then transfer greens to a colander to drain well and press out liquid with back of a large spoon. Make sauce: Combine cream or milk and garlic in small saucepan; bring to simmer; keep warm. Melt two Tbs butter in a medium heavy saucepan over moderate heat and stir in flour. Cook roux, whisking, 1 minute, then slowly whisk in warm cream/milk and boil, whisking, one minute. Season sauce with salt and pepper. Assemble gratin: Preheat oven to 400°F. Butter deep 9×13 baking dish. Spread half of sweet potatoes in the prepared baking dish. Sprinkle with salt, pepper, 1/4 of the herbs and a 1/4 cup of the cheese. Put half of the greens mixture over the cheese, then sprinkle salt, pepper, 1/4 of the herbs and 1/4 cup of the cheese over it. Pour half of bechamel sauce over the first two layers then continue with the remaining sweet potatoes, more salt, pepper, herbs and cheese and then the remaining greens, salt, pepper and herbs. Pour the remaining sauce over the top of the gratin, pressing the vegetables slightly to ensure that they are as submerged as possible. Sprinkle with the last 1/4 cup of cheese. Bake gratin for about 1 hour until golden and bubbly, and most of the liquid is absorbed. Let stand 10 mns before serving.