When banana bread sinks in the middle it happens for a few reasons. Your banana bread may not be done cooking in the middle, your bananas may have been very large (extra moisture), your oven temp may be off, or you may have mis-measured the baking soda.u003cbr/u003eu003cbr/u003eIf this happens you can place your banana bread back in the oven to cook longer. If it seems like the top is burning you can place a sheet of aluminum foil over the top to help prevent it from overcooking in those areas.