I think what you are speaking of is the grand buffet offered in the DLH ballroom...they have this HUGE, gorgeously decorated, fabulous layout of food experience on Easter, Mother's Day, and Thanksgiving...However, it isnt offered for Christmas which I personally think they should...it would be fabulous and they could charge quite a bit and people would pay it for sure...as it stands now, the parks do not have a special Christmas menu but all 3 of the hotels do and also restaurants in DD do...you probably want to check with them as soon as you can because it will be packed and Im 99% sure you will HAVE to have a reservation...
oh and also there is a fabulous restaurant in Anaheim that has been voted best in anaheim for many years and it is called The Anaheim White House...Ive eaten there a couple times in the past but not recently...I remember when we went, they sent a limo to pick us up and bring us to the restaurant and then brought us back to our hotel both times...I think they do a special Christmas dinner you might want to look into...the food is really good