Preheat oven to 375°F. In a deep, 2 quart baking of soufflé dish melt the butter in the microwave. Whisk in the superfine sugar and banana, mashing until thoroughly combined. Whisk in the egg and milk.
In a bowl, whisk the flour, baking powder and salt; whisk into the baking dish until combined (the batter will be pretty loose).
In a microwave-safe cup, heat the maple syrup, light brown sugar and ½ cup of hot water at high power until hot, 1 minute. Add the bourbon. Drizzle the syrup mixture over the batter; it will seep to the bottom. Do not stir. Scatter the pecans on top.
Set the dish on a rimmed baking sheet and bake for 40 - 45 minutes, until the cake is golden. Let cool for 5 minutes, them scoop into bowls and serve with ice cream.
Notes
I used a frozen banana that I'd thawed out overnight. I always toss whole bananas directly into the freezer if they get too ripe for just such occasions and they work great!