Peel and roughly chop the bananas, then measure. Place into a mixing bowl and mash with a fork until mostly smooth with small lumps remaining.
Combine the melted butter and brown sugar in a saucepan over medium heat. Stir continuously until the mixture just begins to bubble and turns a deep amber color, indicating caramelization.
3 large ripe bananas
Pour the hot caramel mixture into the mashed bananas, stirring quickly to blend and incorporate the caramel evenly. The mixture should be smooth and glossy.
3 large ripe bananas
Preheat the oven to 350°F (175°C). In a separate bowl, whisk together the flour, baking powder, and salt. Add this dry mixture to the banana-caramel mixture, gently folding until just combined.
3 large ripe bananas
Transfer the batter into a greased baking dish or springform pan. Spread evenly with a spatula. Bake in the preheated oven for 35-40 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean. You should hear a slight bubbling sound from the caramel as it bakes.
Remove from the oven and let cool slightly. The top should be sticky and crumbly with caramelized edges. Serve warm or at room temperature, displaying a glossy, caramelized surface and tender, jammy interior.
