4 just ripe bananas, sliced 1/2-inch thick on the bias
powdered sugar, for dusting
To make the sauce, combine the coffee, sugar, and half of the Kahlúa in a small saucepan.
Place over medium heat and stir until the sugar is dissolved. Bring to a boil and cook until mixture is thick and syrupy, about 10 minutes. You might need to stir towards the end to prevent the mixture from boiling over—watch carefully.
Remove from the stove and add the remaining Kahlúa, bring back to a boil then remove from heat. Set aside to cool. Sauce can be made up to a week in advance, covered and refrigerated until ready to use.
For the fritters, pour about 2 inches of oil into a deep frying pan and heat over medium heat to between 350-375°F, or until a piece of bread dropped in the oil browns in 30 seconds.
Meanwhile, combine flour, sugar, salt, baking powder, and cinnamon in a large bowl. Whisk aerated and break up any lumps. Make a well in the middle.
Add the egg and coconut milk to the well in the middle of the flour and stir until combined and smooth.
Add the banana about 5-6 pieces at a time to the batter and coat on all sides.
Lift the banana slices, one at a time, out of the batter and let any excess drip back into the bowl. Carefully place the banana slices into the hot oil and fry for 6-8 minutes, turning halfway through.
Remove fritters to a paper towel-lined tray and repeat with the remaining banana slices.
Serve fritters warm, dusted with powdered sugar and drizzled with coffee sauce.