How to cook
First sift the flour, cocoa and baking powder and put them to the side. Add the baking soda to this mixture. Beat (best to use a mixer or whisk) the egg, sugar, oil and yogurt, adding the products one by one.
After beating well, pour a little bit of the flour mixture in at a time, while stirring constantly with a mixer to get fluffy and delicious chocolate muffins. Next, add the chopped into small pieces or mashed bananas and mix with a spoon.
In each muffin form, put a paper basket and with a spoon pour the mixture in. Be careful not to fill the forms of muffins to the top, because during baking the muffins will rise and spill out. Also, if you're using too much mixture, it's possible that the muffins won't bake well.
Fill the forms to 2/3 of their volume. Bake the chocolate banana muffins in a preheated 360°F (180 °C) oven. The muffins are ready when after poking them, the toothpick comes out clean.
Decorate as desired :))