Step 1

Line a 9-inch (23-cm) springform pan or baking pan with a parchment round.

Step 2

Whisk together the ground flaxseed and water in a small mixing bowl. Set aside for 5 minutes to thicken.

Step 3

Add the sugar and water to a small saucepan and stir to combine. Turn the heat on medium-low and cook, without stirring, but swirling the pot occasionally, until the mixture is bubbly and has turned a light amber color, about 8 to 10 minutes. Take the pan off the heat and set it aside.In the meantime, add the coconut milk, miso, butter, and salt to a separate small saucepan. Use a small silicone spatula to break up the miso. Turn the heat on low and whisk to work the miso into the coconut milk and butter, until the mixture is completely smooth and warm.

Step 4

Slowly pour the warm coconut milk–miso–butter mixture into the sugar and quickly whisk it together. Be careful; it will bubble up and will be wicked hot. Cover and let cool.If not using immediately, store in an airtight container in the refrigerator for up to 3 days or in the freezer for up to 3 months. Bring to room temperature before using.

Step 5

Pour the Sweet Buttery Miso Caramel into the pan and use an offset spatula or the back of a spoon to spread it in a thin layer as close to the edges as you can. Lay the bananas on top of the caramel, with their flat sides facing down and their rounded sides facing up, so when the cake is flipped upside down, the cut side will be facing up. Set aside.

Step 6

Add the flour, baking soda, zest, and salt to a big mixing bowl. Add the flax eggs, yogurt, sugar, sunflower oil, lemon juice, and vanilla. Mix, using a hand mixer on low, until the batter is smooth.Pour the batter over the bananas.

Step 7

Or until the top is golden brown and a tester comes out clean.

Step 8

Carefully invert the cake onto a serving platter and release the springform pan or tap the top to release the cake. Remove the parchment round. Cool completely before serving.