2 tablespoons extra virgin olive oil
8 large shallots, finely chopped
8 whole scallions, thickly sliced
16 ounces baby spinach leaves, roughly chopped
Kosher salt and cracked black pepper
2 cups Greek Bechamel Sauce, see below
1/3 cup roughly chopped dill
3/4 cup plus 1 1/4 cup coarsely grated graviera cheese
1/2 cup plus 3/4 cup crumbled feta cheese
8 cups cooked elbow macaroni
1. In a large, heavy pot, warm the olive oil over medium heat.
2. Add the shallots and cook until softened, about 3 to 4 minutes.
3. Add the scallions and spinach, and cover the pan for a minute, to begin wilting the spinach. Toss for 1 to 3 more minutes, to wilt without melting completely. Season liberally with kosher salt and pepper.
4. Thoroughly stir in the Greek Bechamel Sauce (recipe below), dill, 3/4 cup graviera, and 1/2 cup feta.
5. Combine creamed spinach mixture with the 8 cups cooked elbow macaroni and the remaining 3/4 cup crumbled feta.
6. Turn into a 9 x 12-inch or similar-sized gratin dish and top with some toasted bread crumbs (homemade, or, in a pinch, store-bought) and the remaining 1 1/4 cups grated graviera. Bake at 350° until warmed through, and then broil for a minute to brown the top.
Greek Bechamel Sauce
2 1/2 ounces unsalted butter
5 ounces all-purpose flour
3 1/4 cups whole milk, warm
1 teaspoon ground cinnamon
Pinch nutmeg, preferably fresh ground
1/2 to 1 teaspoon kosher salt
Cracked black pepper
1. In a large, heavy pot, melt the butter over very low heat, whisking with a large balloon whisk. Add the flour and whisk to a very crumbly roux, not a smooth paste. Whisk constantly and energetically for about 5 minutes to cook off the raw flour taste, but do not allow to brown (slide the pot on and off the heat every now and then if you sense it is getting too hot).
2. Still whisking constantly, drizzle in the warm milk until smooth. Continue cooking, adjusting the heat as necessary to keep the mixture at a very low simmer, until very thick. Whisk in the cinnamon, nutmeg, kosher salt to taste, and a generous amount of pepper.