Beat the butter and sugar till fluffy. Add the eggs, banana and vanilla and beat till combined.
In another bowl, whisk together all the dry ingredients well. Add the wet ingredients and fold in with a spatula till the batter is moist. Chill in the fridge for 30 minutes.
Preheat oven to 180 degrees. Keep a baking tray lined with parchment paper.
Using an ice cream scoop or a tablespoon, scoop out the dough and drop on the tray. Keep sufficient spacing in between for the cookies to spread. I made the cookies as batch of 6.
Bake for 10-12 minutes till done. Transfer onto a cooling rack and cool completely.
Makes 18 cookies.