FOR FRENCH TOAST:
PREHEAT oven to 350° F. Spray 3-quart or 13 x 9-inch baking dish with nonstick cooking spray.
PLACE bread slices on large baking sheet. Bake, flipping bread slices halfway through, for 25 minutes or until dry and just golden. Turn off oven. Cut bread slices in half; layer in prepared baking dish.
WHISK together eggs in large bowl; whisk in evaporated milk, sugar, vanilla extract, cinnamon and nutmeg. Pour over bread, pressing bread to submerge. Spoon some of the mixture between the slices if needed. Cover tightly and refrigerate for at least 8 hours or overnight.
FOR PRALINE TOPPING:
PREHEAT oven to 350° F.
COMBINE butter, brown sugar, cinnamon and nutmeg in large bowl; stir until smooth. Stir in pecans until coated. Uncover casserole; sprinkle evenly with pecan topping.
BAKE for 45 to 50 minutes or until puffed and golden brown. Sprinkle with powdered sugar. Serve with maple syrup. Serve immediately.