Boil the cauliflower florets with the teaspoon of salt for 10-15 minutes until soft. Drain, mash well, then set aside.
Add the butter to a large frying pan. Once melted and hot, add the flour and stir for about 1 minute. Finally, add the hot milk and stir well. The sauce should start to thicken.
Once thickened, remove from the heat.
Add the salt, pepper, and egg yolks to the sauce and mix well. Then, mix in the shredded cheese and mashed cauliflower.
Once the cheese has melted, add the parsley and stir again.
In a separate large bowl, beat the egg whites until stiff.
Fold the cauliflower mixture very gently into the egg white mixture.
Preheat the oven to 350°F (180°C). Spoon this mixture into 6 individual ramekins or a large casserole dish. The mixture will rise quite a bit while cooking, so don’t overfill the containers.
Bake for 40 – 45 minutes until the tops are golden and the mixture is firm, then remove from the oven.