Yes! You can prepare the eggplant 5 days in advance; just store it in an airtight container in the fridge. You can also make the bharta several days in advance and store it separately. Leftover baingan bharta will stay good in the fridge for 5 to 6 days; you can also freeze it for a few months with good results. To reheat, microwave or add to a frying pan on medium-low heat until warmed through.