Butter room temperature beat (a minute or two), add sugar. Beat for another couple of minutes, then add the egg and whisk for another minute (I beat everything by hand). Sift flour with soda, salt and baking powder (honestly, I don't know why both in the recipe, but did as the author). Bananas grind in a blender until mushy state. Add to the oil weight banana and stir with a spoon. Then add flour and stir. Divide into two equal parts and in one add the sifted cocoa, stir.

Nuts and chocolate to chop, but not very finely. In form (I have silicone, rectangle, for it seemed to me too much dough, so I made another batch of cupcakes) pour the chocolate dough, put nuts and chocolate

then the light dough. Put in oven (180град.) for about 40 minutes (the time depends on your oven, test with a wooden skewer)

Prepare the glaze. Powdered sugar mix with lemon juice, spread on top of pie and sprinkle with grated lemon zest.