FOR THE PUDDING:
In a large saucepan combine the milk, cornstarch, sugar, salt, and cinnamon stick over medium-low heat. Stir occassionally. Meanwhile, beat the egg yolks together in a medium-sized bowl.
Once milk mixture thickens, reduce to low heat. Then add a few spoonfuls slowly to the egg yolks to temper them. Slowly incorporate the egg yolk mixture back into the milk mixture.
Continue stirring occassionally until mixture is thick enough to coat the back of a spoon. Remove cinnamon stick then remove pudding from heat and pour into individual dishes or into one large, shallow dish.
Cover with plastic wrap and gently press the plastic wrap down over the pudding so it does not develop a skin while cooling. Refrigerate.
FOR THE BANANAS FOSTER A LA CHESLI:
In a deep skillet combine the butter, sugar, and cinnamon over medium heat. Stir until butter melts and sugar dissolves, beginning to bubble as if caramel.
Add the plantain slices and stir to coat. Continue cooking, stirring occassionally, until they deepen in color, are soft, and the sugar mixture reaches a good medium caramel color.
Get out a match and matchbox ready in order to light the flame with the cognac. Carefully add the cognac to the banana mixture. Wait just a few seconds for it to heat up slightly, then light it on fire! (This is fun but PLEASE be careful. I suggest you first check to make sure nothing flammable is within 2 feet above the pan and that you quickly touch the match to an area where you see cognac on the surface then snap back your hand so it doesn't get burnt).
Tilt the pan around to distribute the cognac and the flame. Wait for the flame to subside then remove pan from heat.
While the plantain mixture cools slightly, remove the pudding from the refrigerator. To serve, place cookies around the edges of the pudding(if using smaller containers) then spoon the plantain mixture over the pudding in middle. If using a larger pan like a 13 x 9 place cookies over the pudding then spoon the banana mixture on top of them.