Why did my banana bread fall in the center?

Leavening agents create air bubbles in the batter, which is what causes the bread to rise. Baking sets these air bubbles so they remain in the finished product. But if the banana bread is not done in the middle, the structure doesn’t set properly. That’s often why banana bread collapses when cooling.

Why Does banana bread cave in the middle?

Overmixing your batter develops the gluten in your flour, which gives a dense filling to your soft bread. Using too much banana is not suitable for your bread. While there’s no harm in eating bananas in a more considerable amount, placing too much banana will produce a heavy mixture with excessive moisture.