Preheat the oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.

Combine the dates, pecans, water, banana, egg, butter, and vanilla extract in a bowl.

Whisk flour, baking powder, cinnamon, and salt together in a separate bowl. Add to the date mixture and stir until well combined.

Drop dough by tablespoonfuls about 1 inch apart onto the prepared baking sheet and flatten lightly with the palm of your hand.

Bake in the preheated oven until cookies start to brown around the edges, being careful not to over-bake, for 11 to 13 minutes. Transfer cookies immediately to a wire rack to cool.