Grease a 9"x13" casserole dish with vegetable oil or butter. Fill the dish about three-quarters full with cubed French bread.

In a large bowl, whisk together the eggs, 2% milk, vanilla extract, cinnamon, and brown sugar until smooth.

Pour the custard mixture evenly over the cubed French bread, ensuring all cubes are soaked.

Slice the strawberries and sprinkle them over the soaked bread mixture. Add the blueberries on top.

Cover the casserole tightly with plastic wrap and refrigerate for at least four hours or overnight.

Preheat the oven to 350°F (175°C).

Remove the plastic wrap and bake the casserole for 35 to 50 minutes, checking for doneness at 35 minutes.

Once baked, sprinkle with powdered sugar and serve warm with maple syrup.