Most of the vipassana retreats I've been involved with have been in Australia though some in India and NZ where there have been some variations on the menu items.
In Australia, I think there is a common cookbook for the SN Goenka retreat centres. I was the kitchen manager on one course about 20 years ago. Breakfast - as Retro has said - is characterised by porridge with muesli, stewed fruit & yogurt on the side and toast and its multifarious breakfast condiments and access to a variety of herbal and black tea. The lunch menu changes nearly everyday on a 10-day course. From memory, some of the dishes include stir-fry vegetables and tofu with ginger and soy with brown rice, mild curry with raita and dahl, lasagne, baked vegetables. Every day a salad is also offered. Every second or third day a desert is also offered in the form of home-made 'anzac'-style biscuits (rolled oats, sultanas, sugar), carob balls, something similar to sticky date pudding with custard.
Most of the 'new students' go nuts over the food and most 10-day courses I've sat I've witnessed students on the last day requesting recipes. Personally, I think its due to nine-days of noble silence, 12+ hours meditation per day and the absence of any other sensory pleasure that distorts the perception that the quality of the food is spectacular. The more courses I do, the more I am revolted by the food and the less of it I eat!
If I were to design a menu for a retreat, I would keep the menu nutritious but simple. I'm a believer in ensuring that the food doesn't become a pre-occupation for the participants.