Preheat the oven to 300 degrees. Over medium heat, melt the butter in a saute pan. Add the bananas, and sprinkle with 1 tablespoon of white sugar. Stir well to blend the sugar and butter. Cook, stirring occasionally, for 5 minutes. The bananas should be lightly caramelized. Mash the bananas with the back of a wooden spoon. Add the lemon juice to the mixture, raise the heat to high, add the brandy, and boil for 1 minute. Remove from heat, divide among 6 wide, shallow creme brulee dishes, and let cool. Place the heavy cream in a saucepan. Split the vanilla bean lengthwise, and scrape the seeds into the cream with the tip of a knife. Add the scraped-out vanilla bean, and bring the cream just to a boil, then remove from heat. Reserve. Place the egg yolks and 5 tablespoons of white sugar in the top of a double boiler. Whisk them together, then stir over simmering water until the mixture becomes fairly thick (about 15 minutes). Strain the reserved cream into eggs, and stir the mixture over simmering water for 10 minutes. Remove from heat, and ladle over the cooled banana puree in the 6 dishes. Place the dishes in a roasting pan, and fill the pan with enough hot water to come halfway up the sides of the dishes. Bake in the oven for 40 minutes. Remove the dishes from the pan, and chill them for at least 3 hours.
When you are ready to serve, sprinkle 2 teaspoons of light brown sugar over each dish, distributing evenly. Place the dishes on a bed of cracked ice in a roasting pan, and position the pan under a broiler until the sugar caramelizes. Watch carefully, and move the dishes around so the sugar browns evenly but doesn't char. Remove and serve while the crust is still hot.