Spray a 9 x 13-inch pan with cooking spray. Slice french bread into 1 1/2-inch slices and arrange in two rows in the pan, overlapping each slice half way.
Beat together eggs, heavy cream, milk, champagne, vanilla, and cinnamon in a large bowl. Pour the egg mixture over the french toast, pulling the slices back a bit to evenly coat the bread. Use a basting brush to brunch the egg mixture on the top and bottom sides of the french toast, alternately, you may dunk the slices in the egg mixture before adding to the dish, then pour the remaining egg mixture over the french toast.
Tuck the raspberries in and around the french toast.
Cover with aluminum foil and for at least 2 hours, preferably overnight.
When ready to bake, preheat oven to 350 degrees F. Use a basting brush to brush the egg mixture over the french toast again. Cover back up with aluminum foil and bake for 30 minutes, remove the aluminum foil and bake for another 15 to 20 minutes until all egg mixture has cooked and fluffed up and french toast is golden brown.
Serve with butter, confectioners' sugar, and maple syrup.