To lower the fat use skim milk and fat free cottage cheese. I also omit the salt.
Why does a flourless-seeming egg casserole require a starch thickener at all? Without pastry dough to hold the filling, a standard custard tends to weep liquid as the proteins coagulate in the oven. Incorporating a small amount of flour cooked in butter creates a roux base, trapping moisture within the dairy proteins before baking at 350 degrees.
Melting a quarter pound of butter and whisking in half a cup of flour yields a smooth paste that suspends six large eggs and three distinct dairy products: monterey jack, cream cheese, and cottage cheese. Baking this mixture in a greased 9x13x2 inch pan for 45 minutes promotes even heat distribution across the wide surface area, setting the interior without scorching the dairy solids. Whisking the baking powder into the liquid ingredients introduces tiny air pockets, counteracting the heavy density typical of cheese-heavy bakes.
Adjusting fat content requires careful ratios because removing butterfat alters structural integrity. Substituting skim milk or fat-free cottage cheese reduces overall calories, but additional moisture released during baking may require an extra five minutes in the oven to achieve a firm slice.