Preheat your oven to 350°F (175°C). Line a standard 12-cup muffin tin with paper liners and lightly grease each one to ensure easy release.
In a large bowl, mash the bananas thoroughly with a fork until mostly smooth with just a few small lumps for texture. Add the eggs and whisk the mixture until the consistency is even and cohesive. Stir in the brown sugar until well combined, creating a rich, slightly glossy batter.
Gently fold in the self-rising flour, being careful not to overmix—stir just until no streaks of dry flour remain. If you're adding any extras like chopped nuts, mini chocolate chips, or dried fruit, gently incorporate them at this stage.
Spoon the batter into the prepared muffin cups, filling each about two-thirds full for a nicely domed top. Bake in the center of the oven for approximately 18 minutes, or until a toothpick inserted into the center of a muffin emerges clean.
Allow the muffins to rest in the tin for 5 minutes, then transfer them to a wire rack to cool completely. Enjoy these tender, banana-packed bites as a quick breakfast or a satisfying afternoon snack.