1. Coat bottom and sides of 7×11″ or 9×13″ baking dish with cooking spray (if using the smaller size, bake it much longer due to the depth of the ingredients – – nearly one hour).
2. Place half of the bread pieces in the dish.
3. Scatter the chunks of cheese over the bread.
4. Scatter 1 cup of the berries over the mascarpone cheese.
5. Top with the remaining bread cubes.
6. In a large bowl whisk together the eggs, milk, and syrup.
7. Pour over the bread mixture.
8. With a flat spatula, gently push down the bread so that every piece is soaked in the egg-cream-syrup mixture.
9. Cover and refrigerate overnight.
10. Preheat oven to 350 degrees F.
11. Remove from the refrigerator 30 minutes before baking.
12. Remove foil and bake 30 minutes or more until puffed up.
13. ** As mentioned above, if using the smaller baking pan size, as I did, the baking time is nearly one hour. I also turned the oven up to 375 during the last half hour of baking.

For The Raspberry Sauce

1. Meanwhile, in a small saucepan, whisk together the water, sugar, and cornstarch. Bring to a boil over medium high heat or until thickened.
2. Gently fold in the remaining 1 cup raspberries and the butter.
3. Stir until the butter melts.
4. Remove the French toast from the oven and serve immediately with the sauce.