Sweet Potato and Swiss Chard Gratin
Brought to you by Ariel Rothman!
- 1.5 lbs swiss chard
- 1 lbs sweet potatoes
- 1 Tbsp butter
- 1 small onion, finely chopped
- Pinch nutmeg
- Pinch salt and pepper
- 1 Tbsp fresh parsley, minced
- 1 Tbsp fresh thyme, minced
- ⅔ c Gruyere cheese, coarsely grated
- 1 c whole milk
- 1 garlic clove, minced
- 1 Tbsp butter
- 1 Tbsp flour
Preheat oven to 450°. Separate Swiss chard leaves and stems, and chop both into 1 inch pieces. Slice the sweet potatoes into rounds about 1/8 inch thick. Heat 2 Tablespoons of the butter in a large, heavy pot over medium-low heat, and cook the onion, stirring, until softened.
Add chard stems (not greens), a pinch of nutmeg, salt and pepper, and cook, stirring often, until all the vegetables are tender but not browning. Increase heat to medium-high and add chard leaves in batches, stirring often, until all the greens are wilted. Transfer everything to a colander in the sink to drain. Press with a spoon to release excess liquid.
Make the Béchamel sauce: In a small saucepan, combine milk with garlic and bring to a simmer; keep warm. In a medium saucepan, melt the butter over low heat and stir in the flour to make a roux. Cook the roux, while whisking for about one minute, then slowly whisk in the warm milk. Bring the sauce to a gentle simmer, whisking constantly, and cook about one minute, then remove from heat. Season with salt and pepper.
Butter a 9” x 13” baking dish. Spread half of the sliced sweet potatoes in the bottom of the dish. Sprinkle with salt, pepper, ¼ of the herbs and ¼ of the cheese. Then add half the greens mixture, another ¼ of the herbs and ¼ of the cheese. Pour half the béchamel sauce over the first two layers, and then repeat the process with the remaining ingredients, topping the final layer with the last ¼ of the cheese. Bake the gratin for about half an hour until golden and bubbly, and most of the liquid has been absorbed. Let stand for 10 minutes before serving.