Preheat oven to 300º Spray eight half-cup ramekins with cooking spray.

In a medium saucepan, bring milk to a boil over medium-high heat.

In a 2-quart saucepan, melt the butter over medium heat. Add the flour and nutmeg and stir constantly for 3 minutes. Do not brown. Add the boiling milk all at once, stirring constantly with a whisk. Continue to cook and stir for two more minutes. Remove from the heat and cool slightly.

Pour the mixture into a blender and mix until satin smooth. Pour this into a large bowl. Add the whole eggs one at a time, stirring well after each addition. Add the egg whites, a little at a time, again stirring constantly after each addition. Add the grated cheese and mix until smooth.

Spoon about 1/2 cup of the cheese mixture into each prepared ramekin. Place the filled ramekins in a large baking pan. Add hot water to a depth of 1 inch. Place the pan in the preheated oven and bake for about 30 minutes, or until the flan is set and lightly browned.