Ingredients :

• The bananas — Four medium bananas, and really: the uglier, the better. The skin should be dark brown, almost black in places. At this stage, the pulp is sweet, soft, and concentrated. A pale yellow banana won’t give the same result — you’ll taste the difference from the first bite.
• Buttermilk — This is what makes the cake so moist and tender. No buttermilk on hand? Express version: 240 ml of whole milk with a tablespoon of lemon juice, let it rest for five minutes. It does exactly the same job.
• Butter — At room temperature, truly. Taken out of the fridge at least an hour before. No microwave — melted butter changes the whole structure of the batter. Soft butter creams with the sugar, and that’s where the cake’s aeration comes from.
• Cream cheese — Full-fat version only, not low-fat — too much moisture and your frosting will run. Classic Philadelphia works very well. Take it out of the fridge in advance; it must be soft to mix without lumps.