In a large shallow dish, whisk together the milk, eggs, vanilla extract, cinnamon, orange zest and light brown sugar.
Place a large sauté pan over medium heat and add 2 tablespoons of butter. Once the butter has melted, dip each slice of bread in the egg mixture, coating it on all sides and shaking off any excess, then place it in the pan.
Cook the bread until golden, about 2 minutes, then flip it once and cook it an additional 1 to 2 minutes. Repeat the cooking process, adding more butter as needed, with the remaining slices of bread.
Top the French toast with maple syrup and fresh fruit, if desired, and serve immediately.