Preheat the oven to 160 ° C top / bottom heat. Grease a flat, square baking pan (for brownies) and also line the base with baking paper.
Cut 3 of the bananas lengthways. Brush the bottom of the tray with half of the syrup and place the bananas on top with the cut side down. Mix the butter, sugar, eggs, vanilla essence and the rest of the banana (best cut into small cubes beforehand) with a mixer. Mix in the almonds, flour and baking powder. Then fold in the yogurt. Carefully pour the batter into the baking pan over the bananas.
Bake in the oven for 45-50 minutes. Let cool down.
Then poke small holes all over the cake with a fork and then spread the rest of the syrup over it and let it soak in (this makes the cake so beautifully sticky). Carefully turn the cake over and peel the parchment paper from the banana side.