Slice the brioche or challah bread thickly and set them in a baking dish greased lightly.
In a mixing bowl, combine eggs, milk, cream, sugar, vanilla, cinnamon, and salt; whisk thoroughly until smooth.
Pour the custard mixture evenly over the bread, pressing down lightly so the slices absorb the custard. Cover and chill in the fridge for at least 30 minutes, ideally overnight.
Warm your oven to 350°F (175°C) while the bread soaks.
Take the baking dish out of the refrigerator and bake for 25 to 30 minutes until the top turns golden and the custard is fully set. For a crunchier surface, broil for 2 to 3 minutes more.
Sprinkle an even layer of sugar atop the baked French toast and caramelize it with a kitchen torch until crisp and browned. Alternatively, place under the broiler for a minute or two, watching carefully.
Allow the French toast to cool a bit before serving. Garnish with fresh berries, powdered sugar, and a drizzle of maple syrup if you like.