If you have a kitchen scale you could also weigh the casserole dish or skillet or whatever empty, then weigh it again with the cooked food in it. Subtract the two numbers and divide by 6. That would give you the weight of one serving. Then put your plate on the scale, zero it out, and serve up the weight of food you calculated. It is somewhat of a pain, but I have been doing that the first time I make a recipe. Then I note the serving weight down and can use it later without all the extra work. If you want to know cup size or whatever, just take the food you weighed out and put it into your measuring cups, write it down, and you are good to go for now and for the future.
Note though that like was mentioned above, the weight can definitely change given the cooking time, ingredients used, etc, however, this gives an estimate that Im comfortable with.
Edited by: MUSCATDBQ at: 3/3/2013 (19:15)