Preheat oven to 350 degrees. Coat 13” x 9” pan with non-stick cooking spray. Slice croissants horizontally and layer until pan is about 2/3 full. Mix eggs, creamer, half and half, milk, vanilla, and ½ cup sugar. Pour ½ of the egg mixture over croissants.
Mix 1/2 cup sugar with 2 tsp. cinnamon + 1 tsp. nutmeg. Place apple slices in a glass bowl with half of the sugar/ cinnamon/nutmeg mixture and microwave until softened but not done. .
Lay apple slices on top of croissants and pour the remaining egg mixture over apples. Sprinkle remaining sugar mixture over apples.
Cover tightly with foil and refrigerate overnight. Bake for 1 hour. Let stand 10 minutes before slicing.