Since Mother's Day is a day when mom is celebrated and pampered, it would be counter-intuitive to expect her to cook. On the other hand, putting too much burden on the other members of the family (dad and the kids) would also be ill-advised.
There is the classic New Yorker's solution of serving lox, bagels, and cream cheese or avoiding cooking entirely by visiting a restaurant, but a home cooked meal makes such a personal statement.
The key is to prepare a simple meal so you don't spend more time in the kitchen than with her. That and flowers tells her, "I love you."
I have been thinking about all the recipes of everyone I know and it is so funny and interesting the way their personalities play into everything so well and say so much.