Over medium heat, melt 1 tablespoon of butter in a saute pan. Add 3 bananas, coarsely chopped, and sprinkle with 1 tablespoon of sugar. Stir well to blend sugar and butter. Cover and cook for 5 minutes.
Mash bananas with the back of a wooden spoon. Add the juice of 1/4 lemon to the mixture, raise heat to high, add 3 tablespoons Spanish brandy, and boil for 1 minute. Remove from heat, divide among 6 round, shallow, 6" oven-proof dishes, and let cool.
Place 3 cups of heavy cream in a saucepan with 1 vanilla bean. Bring to a boil, then remove from heat. Reserve.
Place 8 egg yolks and 5 tablespoons of sugar in the top of a double boiler. Stir over simmering water until the mixture becomes fairly thick--about 15 minutes. Add the reserved cream with vanilla bean, 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 six dishes in 1/2-inch of water in a roasting pan. Place in the oven, and bake for 40 minutes. When done, remove and chill for at least 1 hour.
When ready to serve, place the dishes on a bed of cracked ice in a roasting pan. Sprinkle 2 teaspoons of light brown sugar over each dish, distributing evenly. Place under a broiler for 3 minutes, or until sugar caramelizes. Remove and serve immediately, or re-chill and serve cold.