Make the dough. Mash the banana with a fork. Add the cottage cheese and condensed milk and mix. Add flour and continue mixing. The mixture should be the same as for syrniki — it should be easy to mold.
Bake the cookies. Line a baking sheet with parchment. Form balls and then cookies from them. They should not be very thick, about 0.5-1 cm. Bake for about 5-10 minutes, until golden brown. Remove from the baking sheet and serve. Enjoy!