Broccoli and Cauliflower Gratin
Every cook needs a few go-to vegetable side dishes in her back pocket. So let us introduce you to one that we want to serve at basically every single meal: broccoli and cauliflower gratin. It brings two veggies together in cheesy harmony, and what could be tastier than that?
5 tablespoons butter, divided
1 sweet onion, finely chopped
1 garlic clove, minced
¼ cup all-purpose flour
1½ cups whole milk
½ cup heavy cream
¼ teaspoon nutmeg
Salt and freshly ground black pepper
1 head broccoli, cut into bite-size florets
1 head cauliflower, cut into bite-size florets
1 cup grated Gruyère cheese
¾ cup grated Parmesan cheese
1. Preheat the oven to 400°F. Grease a 9-by-13-inch casserole dish with 1 tablespoon of the butter.
2. In a medium pot, heat 1 tablespoon of the butter over medium heat. Add the onion and sauté until translucent, 4 to 5 minutes. Add the garlic and cook until fragrant, 1 minute more.
3. Add the remaining 3 tablespoons butter to the pot and melt completely. Stir in the flour to combine. Cook, stirring occasionally, until the mixture is lightly golden in color, 2 to 3 minutes.
4. Add the milk gradually to the pot, using a whisk to combine. Do the same with the cream and then bring the mixture to a simmer, whisking constantly until the sauce is thick enough to coat a spoon, 5 to 7 minutes.
5. Season the sauce with the nutmeg, salt and pepper. Add the broccoli and cauliflower to the pot and toss well to fully coat.
6. Pour the vegetables-and-sauce mixture into the prepared casserole dish. Sprinkle both grated cheeses evenly over the surface.
7. Bake until the sauce is bubbly and the cheese is golden, 35 to 40 minutes. Let sit 5 to 10 minutes before serving warm.