Boil milk. In a separate saucepan melt margarine and add flour to make a roux. Slowly add hot milk whisking constantly. In a small bowl whisk egg yolks and add a little warm milk to temper egg yolks. Stir egg yolk mixture back into the pot with the warm milk. Add cheese and stir to combine. Remove from heat and cool. Beat egg whites until stiff peaks form and fold into the cooled custard. Ladle custard into 6 greased ramekins. Put ramekins into a large pan and pour warm water into pan until water reaches 1/2 way up the sides of the ramekins. Bake in a preheated 450 degree oven for 5 minutes, reduce temperature to 350 and bake until just set, about 15 to 20 minutes.