Step 1: Prep the Bread and Custard
Lightly spray a 9×9 inch casserole dish with nonstick cooking spray. Distribute the cubed French bread slices evenly across the bottom of the prepared pan. In a medium bowl, whisk together the eggs, milk, vanilla extract, and granulated sugar until well-blended. Carefully pour the custard mixture over the bread cubes, gently pressing the bread down to help it soak up the liquid.

Step 2: Add Fruit and Chill
Top the soaked bread with a single, even layer of the sliced peaches. Cover the dish tightly with plastic wrap and set it in the refrigerator to chill for at least 2 to 3 hours, or preferably, overnight. (Do not skip this step!)

Step 3: Prepare the Topping and Preheat
Preheat your oven to 350°F (175°C). In a small bowl, combine the melted butter, 1/4 cup granulated sugar, and all-purpose flour for the cobbler topping. Mix with a spoon until the mixture is uniform and forms a coarse crumble.

Step 4: Bake the Casserole
Uncover the chilled casserole and sprinkle the crumble topping evenly over the surface of the peaches. Bake at 350°F (175°C) for 30 to 35 minutes. The bake is complete when the center is completely set (no jiggle) and the cobbler topping is a crisp, golden-brown color.

Step 5: Serve
Remove the French Toast Bake from the oven and allow it to cool for a few minutes before slicing and serving warm, with a drizzle of maple syrup or a dollop of whipped cream, if desired.