For the Apple Mixture:
Melt butter in a large sauté pan, over medium heat. Add brown sugar and stir until completely incorporated. Transfer chopped apples to pan and stir until coated with sugar mixture. Cook for 5 minutes while stirring frequently. In a small bowl, stir together the corn starch and warm water. Add the corn starch mixture to apples and continue to cook/stir for 5 more minutes. Remove from heat and set aside while prepping the other ingredients. The apples should be soft and the liquid will be a syrup consistency.
For the Casserole:
Preheat oven to 375°F.
Whisk together the heavy cream, Musselman's Apple Butter, eggs and cinnamon. Spray 9x11 casserole dish with non-stick. Place the bottom halves of the croissants in an even layer. Pour half of the apple butter/cream mixture over the croissants. Top with half of the caramelized apple mixture. Arrange the croissant tops in an even layer. Top with the remaining cream mixture and apples. Pour all of the syrupy apple mixture over the casserole. Gently press down on the top with a wooden spoon or spatula. Bake at 375° for 25 minutes. Once lightly browned on top; remove from oven, glaze and serve.
For the Glaze:
Mix powdered sugar and heavy cream together with a fork until smooth. Drizzle over the Apple Fritter Casserole. (These measurements yield 1/2 cup of glaze.)