It's impossible to say without looking at the recipe - the calorie content can vary drastically depending how much cheese you use, how many noodles....
If you can remember how many noodles went in, pull some dry ones out of the cupboard and weigh them, to determine how many calories of pasta went in. You can probably take a good guess at how much cheese... find out the calories for that. How much meat (if any) went in? Tally it all up, and you will come up with a calorie count for the entire pan. Then consider how much of the pan did you eat? 1/4? 1/6? 1/8? Divide accordingly, now you know your calories for your "serving size."
It's a pain to figure out the first time - but if you put your basic recipe into the Recipe Calculator, you only have to do it once, then when eating future lasagnes you can just pick the item off your saved recipes, and won't have to recalculate the whole darned thing again.
Goal 1 - break 200 (46 pounds lost)**DONE**
Goal 2 - leave obesity behind (BMI 29.9, at 185#) **DONE**
Goal 3 - BMI = Normal (154# or less)
| current weight: 174.0