Yield: 6 to 8 servings.
1 tablespoon unsalted butter, softened
1 (1-pound) loaf French bread, torn into pieces
1 cup coarsely broken graham crackers
2 tablespoons unsalted butter, melted
½ teaspoon salt
1 (14-ounce) can sweetened condensed milk
1 cup whole milk
1 teaspoon vanilla extract
1 cup high-quality dark chocolate chips, divided (we used Ghirardelli)
Preheat oven to 350°. Prepare a 9 x 12-inch baking dish with 1 tablespoon softened butter.
Place French bread on a sheet pan and bake for 8 to 10 minutes or until golden brown. Place toasted bread in baking dish.
Place broken graham crackers on sheet pan and drizzle with 2 tablespoons melted butter. Bake graham crackers for 5 minutes or until lightly browned. Remove from oven and sprinkle with salt. Set aside.
In a medium bowl, whisk together eggs, sweetened condensed milk, whole milk, and vanilla. Place the marshmallows and the chocolate chips over the bread so that they are evenly distributed. Pour the egg mixture over the bread and lightly press down to make sure all of the bread is coated. Let bread sit for 5 minutes.
Bake for 35 to 40 minutes until the egg mixture is cooked and set. The center should be slightly springy but not firm. Remove from oven and place toasted graham crackers on top, lightly pressing edges into the top. Serve warm.