Set oven to 350F.
In a bowl, mash up the banana with a fork. Then add nut butter and vanilla extract and mix well.
Add the remaining ingredients (except the walnuts and carrots) and mix well – it should be thick and sticky like cookie batter.
Fold in walnuts and carrots and mix in using your hands.
Line a baking tray with parchment, then use an ice cream scoop to evenly measure out 15 cookies. Add them to the baking tray and lightly mash down with a fork or spatula to shape the cookie.
Bake for 12-15 minutes, until the outside is golden brown. Be careful not to over bake them since they may not change color too much but 10 -12 minutes in the oven should be sufficient.
Allow them to slightly cool on a baking tray or a paper towel before enjoying.