Preheat your oven to 350 degrees f. and line an 8x12 inch baking pan with parchment paper.
Place your 3 whole bananas into a mixing bowl and mash them using a fork.
Add in the honey/maple syrup, oil, egg and vanilla, and whisk until well incorporated.
In a separate bowl, whisk together all remaining ingredients. Add this into the bowl with the banana egg mixture, and stir gently to completely combine.
Pour your batter into the prepared baking pan and smooth the top and sprinkle with a few extra chocolate chips if desired. Add thin banana slices arranged equally on top as shown.
Bake for 18-20 minutes, or just until the top is golden and a toothpick inserted in the center comes out clean.
Allow to cool completely before slicing into bars.
Keep these refrigerated for up to 5 days.