Depending on the vegetable you choose or have, the the prep will be different. Cauliflower and broccoli are the same...blanch them for 5 minutes. Squash maybe only 3 minutes, Green beans maybe 5 but something like potatoes would take maybe 15. I have even made a gratin with green onions, leeks and even celery. You just have to judge how much extra pre-cooking time in order for the vegetable to be done after the short baking time since you are really just browning the top and heating it through. Anyhow, on to the cauliflower(mine is one of the orange ones!).
- 1 (3-pound) head cauliflower, cut into large florets
- Kosher salt
- 4 tablespoons (1/2 stick) unsalted butter, divided
- 3 tablespoons all-purpose flour
- 2 cups milk
- 1/2 teaspoon freshly ground black pepper
- 1/4 teaspoon grated nutmeg (not absolutely necessary but it really makes a cream sauce)
- 3/4 cup freshly grated Extra-Sharp Cheddar cheese, divided
- 1/2 cup freshly grated Parmesan
- 1/4 cup fresh bread crumbs
Preheat the oven to 375 degrees F.
Cook the cauliflower florets in a large pot of boiling salted water for 5 to 6 minutes, until tender but still firm. Drain. Note: If you are using a green vegetable like broccoli, green beans, green onions, etc. then you need to refresh them with cold water after the blanching so that they will keep their color.
While the cauliflower or whatever cooks, 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 to cook the flour. Pour all of the milk into the butter-flour mixture and stir with a whisk until it starts to bubble. This is nothing more than a light white sauce. Simmer, whisking constantly, for maybe a minute, usually once it starts to boil it will be at its maximum thickness. Off the heat, add 1 teaspoon of salt, the pepper, nutmeg, 1/2 cup of the cheese, and the Parmesan or a whole cup of cheese and skip the Parmesan. Stir until the cheese melts and it all comes together into a smooth sauce.
Pour a third of the sauce on the bottom of an 8 x 11 x 2-inch baking dish or a 9x12 if that's what you have. Place the drained cauliflower on top and then spread the rest of the white sauce evenly over the top. Combine the bread crumbs with the remaining 1/4 cup of cheese and sprinkle evenly 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. you can serve it hot or at room temperature but I prefer it hot.
You can use this as a one dish meal by just putting a nice salad on the side or as a side dish. Left overs will keep in the fridge for a few days and don't suffer too much when heated in the micro wave.
Try this with other vegetables and you will be glad to have this in your arsenal. You can gratin anything as long as you have the weapon of white sauce with cheese.