cauliflower cheese baked potato
4 baking potatoes, russet or idaho (each about 8 ounces, or 225 grams)
1 large (2½-to-3-pound, or 1130-to-1360-gram) head cauliflower, cut into medium florets
Kosher salt, and freshly ground pepper or ground cayenne 4 tablespoons (55 grams, or 2 ounces) unsalted butter 1 medium leek, white and light-green parts, halved lengthwise, cleaned, thinly sliced 4 tablespoons (35 grams, or 1 ounce) all-purpose flour 2 teaspoons mustard powder, or ¾ teaspoon smooth Dijon mustard
Ground cayenne pepper (optional)
2 cups (475 grams) milk, whole or low-fat
1¼ cups plus 2 tablespoons
(about 155 grams, or 51/ ounces, total) grated sharp cheddar 2 tablespoons minced fresh chives, for garnish (optional)
Bake the potatoes: Heat the oven to 450°F (230°C). Pierce the potatoes all over with a fork, and rub them with 1 tablespoon olive oil. Place the potatoes on the oven rack, and bake for 1 hour, or until tender in the center when pierced with a skewer.
While the potatoes bake, prepare the cauliflower: Coat a baking sheet with 2 tablespoons olive oil. Add the cauliflower florets, and toss to coat.
Season well with salt and pepper. Roast for 25 to 30 minutes total, tossing once, until nicely browned at the edges. Let the cauliflower cool while the potatoes finish.
Meanwhile, make the sauce: In a medium saucepan, melt the butter over medium heat. Add the sliced leek, and cook until softened, about 8 to 10 minutes. Add the flour, and whisk to combine; cook for 1 minute to ensure you get rid of the floury taste. Add the mustard powder and a pinch of cayenne or few grinds of black pepper, and stir to combine. Drizzle in the milk in a thin, steady stream, whisking the whole time so that no lumps form.
Season with salt, and bring the mixture to a simmer, stirring with a spoon; the sauce should begin to thicken. Remove from the heat, and stir in 1% cups grated cheddar, a handful at a time, letting each handful mei before adding the next. Taste the sauce, and adjust seasonings if needed.
Add the roasted cauliflower, and stir until it's coated with sauce.
Assemble potatoes: Once the potatoes are ready, slice them in hale lengthwise, and, using a pot holder, arrange them snugly, cut side up, in a
9-by-13-inch baking dish. Season the cut sides with salt and pepper, and use the tip of a knife to score them in a grid, cutting 1/ to 1 inch into the potato. Spoon the cauliflower cheese sauce over each potato. Sprinkle them with the remaining cheddar, and return them to the oven to cook until the cauliflower topping is browned, 5 to 10 minutes.
To serve: Scatter with chives, if desired. Serve with sour cream.