If you're serving the gingerbread french toast to a larger group, here's how to keep it warm:  After cooking, place gingerbread French toast on a baking sheet and transfer them into the oven. They will stay warm for about 20 minutes. If you don't have an oven to keep them in, transfer gingerbread french toast onto a baking sheet and cover with foil. The gingerbread french toast will be good for 5 days so that you can make them the day before your party. This way, they stay nice and fresh until you serve them.