Preheat your oven to 350°F (177°C) and line an 8x8 inch baking pan with parchment paper.

In a large mixing bowl, combine the mashed bananas and eggs. Whisk until the mixture is smooth and uniform, with no visible egg streaks.

Add the oats and mix well with a spatula. If you're adding any mix-ins, now is the time to do so.

Pour the batter into the prepared baking pan. Use a spatula to spread it evenly and smooth out the surface.

Bake for 20-30 minutes, or until the bars look set and cooked. The top should be lightly golden, and when lightly pressed, it should feel firm and bounce back.

Allow the bars to cool completely before removing them from the pan, cutting, and serving. Store any leftovers in an airtight container in the fridge or freezer.