Start by greasing a 9"x13" casserole dish with butter or vegetable oil. Add the cubed French bread, filling the dish about three-quarters full.

In a separate bowl, whisk together the eggs, milk, vanilla extract, cinnamon, and brown sugar until well combined. Pour this egg mixture over the bread cubes in the casserole dish.

Add the sliced strawberries and blueberries on top of the mixture, distributing them evenly.

Cover the casserole with plastic wrap and let it chill in the refrigerator for four hours or overnight.

Preheat your oven to 350°F. Bake the casserole for 35 to 50 minutes. Check for doneness at 35 minutes, then continue baking if needed.

Before serving, dust with powdered sugar and enjoy it with maple syrup! This dish is perfect for gatherings, especially on cozy weekend mornings.