Gather all ingredients.

Preheat the oven to 350 degrees F (175 degrees C). Line a 9- x 5-inch loaf pan with parchment paper, leaving a 2-inch overhang on all sides; set aside.

Mash 4 of the bananas in a large bowl using a fork until mostly smooth to equal 1 1/2 cups. Add eggs and 1/2 cup brown sugar; stir until combined.

Add flour to the banana mixture; stir until just combined and no dry streaks remain, scraping down the sides of the bowl as needed.

Pour batter into the prepared loaf pan and spread into an even layer.

Slice remaining banana in half lengthwise; lay banana halves over the top, cut side up. Evenly sprinkle remaining 1 tablespoon brown sugar over the top.

Bake in the preheated oven until a wooden pick inserted in the center comes out with a few moist crumbs, 50 to 55 minutes.

Let cool in pan on a wire rack for 15 minutes; using parchment paper overhang, remove loaf from pan and slice.