Steam cauliflower in a large pot with a steamer until tender, about 7-8 minutes. Drain and keep warm.
Whisk together the flour, milk, and nutmeg in a pot over medium heat; cook, stirring often. As mixture begins to thicken stir constantly, this should take about 8-10 minutes. Remove pot from heat and stir in the cheese, chives, and pepper.
Lightly coat the bottom of a shallow baking dish with 1/2 teaspoon of the olive oil. Place the cauliflower in the dish and top with the cheese sauce.
Place torn up bread into a blender and pulse on and off to form coarse crumbs. Add in the parsley and the remaining 1 1/2 teaspoons of the oil and pulse to blend. Sprinkle bread mixture evenly over the cauliflower and cheese.
Bake until bubble and lightly browned, about 15 minutes, serve immediately.