This gratin is a great side dish for your Thanksgiving!
LEEK AND SWISS CHARD GRATIN
3 pounds Swiss chard (large stems discarded)
3 tablespoons extra-virgin olive oil
6 medium leeks (white & tender green parts only, sliced 1/4 inch thick)
3 cloves garlic (minced)
6 tablespoons unsalted butter (more to grease pan)
2/3 cup all-purpose flour
1 quart whole milk
1/2 cup Gruyere cheese (shredded)
1/2 cup Parmigiano-Reggiano cheese (freshly grated)
1/4 teaspoons nutmeg (freshly grated)
3 tablespoons olive oil
Kosher salt and freshly ground black pepper (to taste)
Preheat the oven to 400ºF. Butter a 10-by-15-inch baking dish.
In a large pot of boiling water, blanch the chard in batches until wilted, about 1 minute. Drain the chard, squeeze dry and chop.
Heat olive oil in a heavy bottomed pot. Add the leeks and a pinch of salt. Cover and cook over medium-low heat until tender, about 7 minutes. Uncover, add the garlic and cook, stirring, until fragrant, about 2 minutes. Add the chard, season with salt and pepper then remove from the heat.
In a large saucepan over medium heat, melt the butter. Stir in flour and whisk to form a paste. Gradually whisk in one-third of the milk until smooth, then add the remaining milk. Bring the sauce to a boil, whisking constantly. Reduce the heat to low and cook, stirring often, until thickened, about 15 minutes. Whisk in the cheeses, nutmeg and season with Kosher salt and freshly ground black pepper. Fold the sauce into the leeks and chard.
Transfer the mixture to the prepared baking dish. Bake in the upper third of the oven for about 20 minutes, until bubbling and golden brown on top. Let rest for at least 10 minutes before serving.
– Instead of Swiss Chard, use spinach!
– Build the gratin a day ahead of time. The next day, bring to room temperature and bake as instructed.