We recommend using a very ripe banana that has not been frozen. Once thawed, bananas release too much moisture, which will make the batter too soft and your cookies may spread too much as they bake.
Refrigerating cookie dough for 2 hours helps to firm up the butter so that the cookies do not spread while they bake.
If you are not in a hurry, refrigerate the dough for at least 12 hours before baking. This will allow the dry ingredients to better absorb the humidity of the butter, giving the cookies an even better texture.
Once the balls of cookie dough are frozen, transfer them to an airtight container. They will keep for 3 months in the freezer. You can bake them from frozen by adding 3 to 4 minutes to the cooking time for a total of 19 to 20 minutes.
