Add the cubed french bread, strawberries and blueberries to a lightly greased 2-quart rectangular baking dish.
In a large bowl, mix together the eggs, milk, granulated sugar, and vanilla.
Slowly pour the mixture over the bread making sure to cover all of the bread. Use a spatula or the back of a spoon to lightly press the bread to make sure it is moistened.
Cover and chill in the refrigerator overnight.
Combine the flour, brown sugar and cinnamon. Use a pastry blender or fork to cut in the butter until the pieces are the size of peas. Cover and chill in the refrigerator.
To bake, preheat oven to 350 degrees.
Uncover the french toast and sprinkle the flour mixture over the bread.
Bake uncovered for about 45 minutes or until a knife inserted into the center comes out clean and you can see that the bread at the bottom the dish has browned (if baked in a clear glass dish).
Top with vanilla sauce or syrup and fresh berries and serve while warm.