Cauliflower and Brussels Sprout Gratin

Preheat the oven to 375 degrees F.

Prepare a large bowl filled with ice water and ice. Cook the cauliflower florets in a large pot of boiling salted water for 5 to 6 minutes, until tender but still firm. Drain. Throw the cooked cauliflower into the bowl of ice water to stop them from cooking any further. Bring the pot back up to a boil and put in the quartered Brussels sprouts and cook for 3-4 minutes. While the sprouts are cooking, the cauliflower should be completely cooled. Drain them and set aside. After the Brussels sprouts are done, throw them in the bowl of ice water and ice.

Meanwhile, melt 2 tablespoons of the butter in a medium saucepan over low heat. Add the flour, stirring constantly with a wooden spoon for 2 minutes. Pour the hot milk into the butter-flour mixture and stir until it comes to a boil. Boil, whisking constantly, for 1 minute, or until thickened. Off the heat, add 1 teaspoon of salt, pepper, nutmeg, 1/2 cup of the Gruyere, and the Parmesan.

Pour 1/3 of the sauce on the bottom of an 8 x 11 x 2-inch baking dish. Place the drained cauliflower and brussels sprouts on top and then spread the rest of the sauce evenly on top. Combine the bread crumbs with the remaining 1/4 cup of Gruyere and sprinkle on top. Melt the remaining 2 tablespoons of butter and drizzle over the gratin. Sprinkle with salt and pepper. Bake for 25 to 30 minutes, until the top is browned.