how to cheat some calories out of a bechamel sauce?

froeschli

I've just prepared a moussaka for tomorrow. everything but the bechamel sauce.

it's a variation on the following recipe:
http://greekfood.about.com/od/eggplant/r/moussaka.htm

(i am doing half the size, added some veggies to the tomato sauce, etc)

the current serving (1/4 dish) is 411 calories - but that does not include the bechamel sauce yet.

following the recipe, it would call for:

1/2 cup butter
1/2 cup flour
2 cups milk
4 egg yolks
some nutmeg

that rings some warning bells, without calculating the calories. did i mention i am planning to put cheese on top?

i don't want to be stingy with the calories, but not stupid either.

so i am thinking of using 1/4 cup butter, 3tbsp flour, 2 cups 2% milk, 1 entire egg. and use a couple of spoons of corn starch to thicken if necessary.
i am undecided on whether it is a better idea to add the cheese into the bechamel, or put it on top.

any input?