Melt butter in a large skillet over medium-high heat and add apples.
Cook, stirring constantly, for 5 minutes.
Add brown sugar, water and cinnamon and cook and stir for 10 minutes or until apples are tender.
Spoon apple mixture into a 9 x 13 inch baking dish sprayed with nonstick cooking spray.
Place bread slices over apples.
In a mixing bowl, whisk together eggs, heavy whipping cream and vanilla until well combined.
Pour egg mixture over the bread slices.
Cover the dish with plastic wrap and refrigerate overnight (for about 8 hours).
In the morning, preheat oven to 375 degrees F.
Bake, uncovered, for 35 minutes or until bread is golden brown.
Let sit for 5 minutes before serving.
Serve using a spatula, flipping toast over so the apple mixture is on top.
Serve with whipped cream, if desired.