Cut the French bread into one-inch cubes and arrange them in an even layer in a 9x13 foil tray or casserole dish.
In a large bowl, whisk together the eggs, cream, sugar, cinnamon, vanilla extract, and salt. Pour the egg mixture over the top of the bread until all the pieces are fully coated.
Sprinkle the mixed berries over the top of the casserole, then cover with two layers of aluminum foil.
Place the dish in the freezer for up to three months until you’re ready to start cooking.
Cooking instructions:
When you’re ready to start baking the casserole, transfer the dish to the refrigerator to thaw overnight.
Preheat the oven to 350° and bake covered for 45 to 60 minutes, until the center of the casserole is set.
If desired, serve with syrup, powdered sugar, and whipped cream for topping.