Cut the cauliflower unto florets. Boil for 3 minutes, then drain and set aside.
Preheat the oven to 355˚F. Lightly grease a baking dish and coat with ¼ cup breadcrumbs. Set aside.
In a medium saucepan, melt the butter. Mix in the flour and milk, and bring to a boil. Reduce heat and continue mixing until thickened. Mix in the salt and cheese and set aside.
Separate the egg yolks and egg whites. In the bowl of a stand mixer, whip the egg whites on high until they form stiff peaks.
Mix in the egg yolks into the flour mixture. Then mix in half of the egg whites, followed by the boiled cauliflower. Mix well. Fold in the remaining egg whites.
Pour the mixture into the prepared baking dish, and top with the remaining ¼ cup breadcrumbs.