Preheat oven to 350 degrees. Line two baking pans with parchment paper and set aside. Stir bananas, peanut butter, honey and vanilla. In a small bowl combine oats, flour, flaxseed, milk powder, cinnamon and baking soda. Stir the mixtures together until combined. Using cookie scoop, drop mounds of dough 2 inches apart onto baking sheets. Gently flatten and spread cookies. Bake one sheet at a time for 10-15 minutes until browned. Transfer to wire rack to cool completely. Store in airtight container up to 3 days or freeze up to 2 months.