Step #3 In a small, without stirring, bring the sugar, heavy saucepan, 2 tbsps maple syrup & 1/2 c water to a boil over medium-high heat, & cook for 5 mins.
Step #4 Boil until the caramel is a light golden color or a candy thermometer registers 240º, 5 to 8 mins longer.
Step #5 Working quickly & carefully, remove the thermometer & pour the maple caramel into the prepared cake pan.
Step #6 Set aside.
Step #7 In a large bowl or baking dish, whisk the milk, eggs & the remaining 1/4 c maple syrup.
Step #8 Soak the croissant halves in the custard until moistened, then layer the croissants on top of the maple caramel in the prepared cake pan, pressing down carefully to flatten.
Step #9 Pour any remaining custard over the croissants & let the bread soak & soften, pressing down every once in awhile to flatten the croissants.
Step #10 Set the cake pan In a large-ish roasting pan & carefully pour enough hot water into the roasting pan to reach halfway up the sides of the cake pan.
Step #11 Bake until the croissants are golden & the custard is set (a toothpick inserted in the center of the French toast should come out clean), about 45 mins.
Step #12 Remove the French toast from the hot-water bath, cut into wedges & serve warm.