1. Crush the banana with a fork, add the condensed milk and stir well. Into a banana paste.
2. Cut unsalted butter into small pieces and soften at room temperature (do not melt into a liquid state by heating in water). Add the powdered sugar, stir with a rubber spatula, and then stir and beat with an electric whisk to expand the volume.
3. Add the banana paste to the egg yolk, and use an electric whisk to mix evenly into a paste. Add it to the butter paste several times.
4. Mix low-gluten flour, baking soda powder, and unsweetened cocoa powder through a sieve. Use a rubber spatula to stir in an irregular manner (to prevent the batter from becoming stiff).
5. During the mixing process, you will find that the batter is too dry. Add milk in small portions until it becomes viscous (the dry powder is not visible, and the batter is elastic to the touch, not liquid). At this time, you can try the taste of the batter. If it is not sweet enough, add some powdered sugar or condensed milk (mainly because I forgot the amount of powdered sugar at the time...I was afraid that I would write it less in the past).
6. Brush the mold with oil (corn oil or salad oil), sprinkle a small amount of flour, and discard the excess flour. This makes it easier to take off the film. Put the batter into the piping bag, vertically, and squeeze it into the batter. (This is better than using a rubber spatula directly, it is easier to squeeze out the air)
7. Dip corn oil or salad oil with clean fingers, flatten it, and sprinkle with heat-resistant chocolate for decoration.
8. Preheat the oven at 180 degrees for 10 minutes, and then bake at 180 degrees for 25 to 30 minutes. When it comes out of the oven, poke it in with a small toothpick to see if there is any sticky liquid. If it is not sticky, it means it is cooked.
Tips:1. The bananas used must be well-ripe (that is, the kind that has dark spots on the skin and has a strong aroma. It is best to rot the next day if you don't eat it today!). 2. The butter should be fully blown until it expands. The given amount can make 14 small cakes (5cm in diameter and 3cm in height). 3. After the cake is baked, it will be out of the oven immediately. Don't leave it in the oven. It is better to keep the humidity. 4. The amount of baking soda powder is less than 0.5g, which is mainly used to neutralize the sour taste of the material. It can be used if it is not available, just a little sour. 5. If there is no powdered sugar, use a small amount of hot milk and the same amount of fine sugar, melt and then add and stir.
