Mix the eggs, oil and mashed bananas with the whisk. Then mix the flour, baking powder and baking soda and mix with the egg mixture. Finally, add small pieces of pineapple or apple. If the bananas are not sweet enough, you can also add a little powdered sugar or agave syrup.
Put paper liners in a muffin pan and divide the batter. They are rather small portions, supposed to be for small children. Bake about 10 muffins at 180 degrees or 160 degrees fan-assisted air for about 15-20 minutes, depending on the oven. (Make a chopstick test.)