To reveal the inner elegance of this creamy vegetable, serve your guests individual cauliflower-and-blue-cheese souffles over baby greens.
With rack in the center, heat oven to 400 degrees. Butter six 5-ounce ramekins. Sprinkle inside of each with the Parmesan. Arrange the ramekins, evenly spaced, on a baking pan. Set aside.
Cut the cauliflower into quarters; remove the center core and leaves. Thinly slice about 30 cauliflower florets vertically. Mince remaining cauliflower to yield about 1 cup. Set aside.
In a medium saucepan over medium heat, melt the butter. Whisk in the flour until it is cooked but not brown, about 2 minutes. Whisk in the hot milk until fully incorporated; let cook 3 minutes. Whisk in the egg yolks, one at a time, until fully incorporated. Using a wooden spoon, stir in the cheese, salt, paprika, pepper, and nutmeg, stirring constantly. Once the cheese has melted, stir in the reserved minced cauliflower and the parsley. Cook 2 minutes more. Transfer mixture to a large mixing bowl. Set aside.
In the bowl of an electric mixer, beat the egg whites on low speed until frothy, about 2 minutes. Increase speed to medium, and beat 1 minute more. When egg whites are foamy, increase speed to high, and beat just until they hold soft peaks; do not overbeat egg whites. Using a large rubber spatula, lightly mix a third of the whites into the cheese mixture to lighten it. Fold in the remaining whites, until just combined.
Fill each ramekin with 1/2 cup souffle mixture; smooth the tops. Insert 4 or 5 of the thin cauliflower florets around the edges of each ramekin, poking florets into the souffle mixture with ruffled edge up. Bake until tops are golden brown and mixture is set, 20 to 25 minutes.
Meanwhile, whisk together the vinegar, salt, and pepper in a small bowl. Slowly whisk in the olive oil until combined. Toss the salad greens with the vinaigrette. Just before serving, divide the salad evenly among 6 plates. Remove the souffles from the oven. Use a kitchen towel to hold the ramekins, and invert souffles onto your hand, and then bottom-side down onto the plates with the salad. Serve warm.
Replace the sherry with red-wine vinegar.