In an electric mixer, cream the butter and sugars until a smooth paste is obtained.
Add the vanilla extract and banana puree and mix.
Combine the flour, baking powder, sodium bicarbonate, salt, and banana cubes, then add them to the preparation and mix well.
Refrigerate the dough for 30 minutes.
Preheat the oven to 350 F (180 C).
Line 2 baking sheets with parchment paper.
Take small portions of dough and form balls the size of a golf ball (1 1/4 inches / 3 cm in diameter).
Place them on the prepared baking sheets, spacing them 2 inches (5 cm) apart.
Bake for 10 to 12 minutes.
Remove the biscuits from the oven. They will be puffed and swollen when they come out of the oven, then they will collapse as they cool.
Let the biscuits cool for 5 minutes on the baking sheets before transferring them to a rack.