How to make
Roast the peanuts in a non greased pan (without the ones for decoration), leave them to cool and grind them. I personally prefer to grind them with the thin skins, because they contains a lot of useful substances, but if you prefer, remove them.
Sift the flour into a bowl along with the baking powder. Add the butter in pieces and sugar (fine crystal, or powdered) and rub with your fingers, until completely absorbed.
Mash the banana with a fork, mix with the lemon juice, so that it does not darken, and add it to the flour together with the egg.
Mix a thick and sticky dough and then add the peanuts. If the dough is still thin, add a little more flour, but not too much, because it hardens in the refrigerator afterwards. If desired, you can divide the dough into two and add 1 tsp. of cocoa powder to one part, so that you have two flavors of peanut cookies.
It is left a cool place, covered with cling film and when it hardens, it is formed into balls a little smaller than a walnut. It's a good idea grease your hands with plenty of oil, because it's quite sticky even though it's hard.
The balls are flattened and arranged at a short distance apart in a tray covered with baking paper. In order for them to have an ideal shape, you can reshape them even when they are already on the paper. Add a peanut in the center of each one.
The peanut cookies are baked at 340°F (170°C), until they turn aquire a golden brown color on the edges - about 20-25 minutes per tray (two trays). After they cool down, they are ready to be eaten.
If you want your cookies to become more crunchy, you can bake them, until they aquire a darker color.
The sweetness of the cookies is very balanced, so if you like very sweet things, increase the amount of sugar to 3.5 oz (100 g).