Preheat the oven to 180C/350F and line a baking tray with grease proof paper or a silicone mat.
Place the bananas into a medium sized bowl and mash with a fork until smooth. Add in the applesauce, melted butter, syrup and vanilla extract and mix with a spatula or wooden spoon until well combined.
Add in the oats, cinnamon, baking powder, salt, chia seeds (if using) and dates. Also any additions you might be including.
Mix everything together until the dried ingredients are coated in the wet and the mixture just holds together.
You can make either 2tbsp or 3tbsp sized cookies. I made 3tbsp, so used my 1.5tbsp cookie scoop to place 2 scoops on top of each other onto my baking tray. Then I pressed them into one larger cookie. Place each cookie 1 inch apart. I got ten 3tbsp sized cookies from this recipe; I guesstimate that you would get around fourteen 2tbsp cookies.
For 2tbsp sized cookies, bake in the oven for 8-10 minutes. For 3tbsp sized cookies, bake for 10-12 minutes. Cookies will be very lightly golden and feel a little firm when you touch the top.
Leave to cool completely on the baking tray before storing, at room temperature, in an airtight container, for 1 week.