In a medium-hot pan, melt 2 ounces of butter. After butter melts, but before starting to brown, add walnuts. Reduce heat to medium and lightly cook walnuts until you begin to smell aroma of toasted nuts. Add bananas to walnuts. Cook approximately 3 to 5 minutes or until bananas begin to caramelize. Remove pan from heat (very important, do not add liqueur to pan while still on burner), add banana liqueur and return to heat. If pan is hot enough, let most of the liquid evaporate until removing from heat. Add maple syrup and set aside in serving container. Combine half-and-half, cinnamon, vanilla, eggs, sugar, pinch of salt in shallow bowl. Stir vigorously to combine cinnamon with mixture. Dip challah bread into egg mixture, make sure that bread soaks up liquid.
Heat pan to medium. Melt tablespoon of butter. After butter has melted and before it begins to brown, add 2 slices to pan. Gently lay bread into butter. After approximately 30 to 45 seconds, turn over 1 slice, place brie on cooked side of challah. Place other piece of challah bread on top of brie (uncooked side still facing up). Add more butter if necessary. Cook another minute, turn over, cook 1 more minute. Continue with the remaining bread and cheese in the same manner.
Place on a plate, spoon your syrup mixture on top and enjoy.
Recipe courtesy of The Valley Green Inn, Philadelphia