Preheat the oven to 350°F. Lightly spray an 8x8 inch baking dish with non-stick spray, or line it with parchment paper, and set aside.
In a large bowl, whisk together the oats, flour, baking powder and salt. In another bowl, mash the bananas and whisk them together with the honey, peanut butter, and vanilla until smooth.
Add this mixture to the dry ingredients and stir to combine. Stir in the milk and fold in the chocolate chips.
Spread the batter in the prepared baking dish and bake for 30-35 minutes or until the edges are golden and a toothpick inserted in the center comes out clean.
Allow to cool completely and then slice into squares.
Notes
Store in an airtight container at room temperature for 3-5 days, or freeze for up to 3 months. The bars are tasty either at room temperature or warmed up.