Step 1

Preheat the oven to 400°F with an oven rack in the middle.

Step 2

Start the chocolate cake. Place the butter and half each of the chopped milk and dark chocolate in a large heatproof bowl set over a pan of gently simmering water. Cook, stirring, until most of the chocolate has melted. Remove the bowl from the heat. Add all the remaining ingredients for the cake, including the remaining chocolate, but don’t mix yet. Set aside.

Step 3

For the bananas, put the oil into a 9-inch (28cm) nonstick, ovenproof frying pan and place over medium heat. Tilt the pan to distribute the oil, then arrange the banana slices to cover the bottom of the pan. Reduce the heat to medium and fry for 3 minutes without stirring or flipping.

Step 4

Scatter the butter, maple syrup, vanilla bean paste, and flaky salt evenly over the banana slices. Cook for 5 minutes, swirling the butter and maple syrup around the pan as they form a caramel together. The bananas will soften and caramelize on the bottom, but if you feel they’re burning, lower the heat a little. After 6 minutes, remove the pan from the heat.

Step 5

Mix the cake batter until fully incorporated, then spoon evenly over the bananas. Bake for 12 minutes, rotating the pan halfway, until just set on top but still quite soft and gooey beneath. Let cool for 5 minutes.

Step 6

In a medium bowl, beat the cream, vanilla, and a pinch of salt until soft peaks form.

Step 7

Use a spatula to gently ease the cake away from the sides of the pan. Place a large plate on top of the pan and flip the cake onto it. There’s a good chance some of the banana slices will remain stuck to the pan, but you can just peel them off and replace them, browned side up. Sprinkle the cake with flaky salt, then top with the vanilla whipped cream. Drizzle with some more maple syrup and serve.