Preheat your oven to 180°C (350°F). Line an 8-inch baking pan with parchment paper, leaving overhang for easy removal.
In a large bowl, mash the bananas with a fork until mostly smooth, with small lumps remaining for texture.
Add the honey or maple syrup, nut butter, salt, and vanilla extract to the mashed bananas. Mix thoroughly until the mixture is sticky, smooth, and fragrant.
Stir in the rolled oats until evenly combined. If using, fold in chopped nuts or chocolate chips for extra flavor and texture.
Pour the mixture into the prepared pan. Use a spatula to spread and press it evenly into the corners, compacting slightly for sturdy bars.
Bake in the preheated oven for 20–25 minutes, until the edges are golden brown and the top feels firm to the touch. A toothpick inserted in the center should come out clean.
Remove the pan from the oven and let the bars cool in the pan for 15 minutes. This helps them set and makes slicing easier.
Lift the cooled bars out of the pan using the parchment overhang. Slice into squares or rectangles with a sharp knife.
Let the bars cool completely on a wire rack before serving. Enjoy fresh or store in an airtight container for up to 3 days.
