Ripping into a hot Bananas Foster croissant releases a cloud of steam which fills the air with the scent of bananas, rum, and caramel. Peek through the steam and you'll see layers upon layers of irresistible, flaky pastry.
In a medium-sized saucepan on medium heat, melt butter.
Add brown sugar and stir gently until just melting.
Slowly and carefully add rum (it can flame and splatter).
When the caramel mixture begins to bubble, add banana slices and reduce heat to low.
Carefully turn banana slices to coat with the mixture and continue to cook for two minutes.
Using a slotted spoon, remove and reserve banana slices for filling the croissants.
Continue to cook until caramel is thickened and coats the back of a spoon.
Remove caramel from heat and cool to room temperature.
Put a few of the prepared bananas in the center of each square of dough. It's tempting to use a lot, but if you overstuff the croissant, the dough will get soggy and the finished product won't be crisp and flaky.
Paint a diagonal line of egg wash across one corner of each dough square.
Fold the opposite corner of each dough square diagonally across the prepared bananas until it touches the egg wash line.
Press folded corner of dough all the way down to the table to ensure that there is a tight seal.
Lightly stretch the corner near where you just pinched and then pull it up and over to the underside of the croissant. The weight of the croissant on top of it will keep that seal closed.
Tuck one cooked banana in each open end of the croissant.
Proof (croissant dough only), lightly brush the top and sides of the croissant with egg wash, and bake the dough according to the instructions for your croissant or puff pastry dough.
Drizzle a small amount of reserved caramel sauce over each croissant.
If you can't eat immediately, store in the refrigerator for up to a week. Reheat in the oven at 350 F for 3-4 minutes.
If you take the Craftsy croissant class, you'll see that this is the folding style that Colette uses for her spinach and feta croissants.