Preheat your oven to 350°F (180°C) and line a 12-cup muffin pan with paper liners or lightly grease it.

In a large bowl, whisk together the mashed bananas, eggs, and plain yogurt until fully combined and smooth.

In a separate bowl, mix the wheat bran, whole-wheat flour, baking powder, and cinnamon.

Add the dry ingredients to the wet banana mixture and stir just until combined—don’t overmix or the muffins can become tough.

Gently fold in the blueberries, being careful not to break them up too much.

Divide the batter evenly among the 12 muffin cups; the cups should be about 3/4 full.

Bake for 20 to 23 minutes. Check doneness by inserting a toothpick in the center: it should come out clean or with just a few moist crumbs.

Let the muffins cool in the pan for about 10 minutes, then transfer them onto a wire rack to cool completely.