Swiss Chard And Leek Gratin - cooking recipe

Ingredients

1 1/2 lbs swiss chard, large stems discarded
1 1/2 tablespoons extra-virgin olive oil
3 medium leeks, white and tender green parts only, sliced 1/4 inch thick
salt
1 1/2 garlic cloves, minced
3 tablespoons unsalted butter
1/3 cup all-purpose flour
2 cups milk
1/4 cup gruyere cheese, shredded
1/4 cup parmigiano-reggiano cheese, shredded
1/8 teaspoon nutmeg, freshly grated
black pepper, freshly ground

Preparation

In a large pot of boiling water, blanch the chard until wilted, about 1 minute. Drain the chard, squeeze it dry, and chop. Be sure to remove any excess moisture.
Heat the oil in the pot. Add the leeks and a pinch of salt. Cover and cook over medium to medium low heat, stirring, until tender, 7 minutes. You know your stove -- if it cooks hot make it medium low, if it cooks low, make it medium. Uncover, add the garlic, and cook, stirring, until fragrant. (about 2 minutes). Add the chard, season with salt to taste and remove from the heat.
Preheat the oven to 425 degrees. Butter or grease a 2 qt casserole dish.
In a large saucepan, melt the butter. Stir in the flour over moderate heat to form a paste. Gradually whisk 1/3 of the milk and cook, whisking, until the mixture starts to thicken. Repeat two more times with the remaining milk.
Bring the sauce to a boil, whisking constantly. Reduce the heat to low and cook, whisking often, until thickened and no floury taste remains, about 10-15 minutes. Whisk in the cheeses and the nutmeg. season with salt and pepper.
Combine the sauce and leeks/chard mixture. Season with salt and pepper to taste.
Transfer to the prepared casserole dish. Bake in the upper third of the oven for 25 minutes. Let rest for 10 minutes before serving to prevent burning your mouth.