Preheat oven to 400°F.
Cut 6 (1-inch-thick) diagonal slices from bread, reserving ends for another use.
Measure ingredients needed to cook the French toast.
Whisk eggs, milk, vanilla extract, cinnamon, allspice, and salt together in a large bowl.
Place bread slices in egg mixture and soak, turning to coat, until bread is completely saturated and the custard is absorbed by the bread.
Lightly oil the pan and melt 1 Tablespoon of butter in a frying pan over medium heat.
Working in batches, brown the bread until lightly golden brown. Cook for about 3 minutes, per side. Add additional oil and butter if necessary to the pan.
Transfer the slices of French bread to a rimmed baking sheet.
Bake the French toast in the preheated oven for 12 to 18 minutes until the outside is crisp and slightly puffed.
Serve hot with maple syrup or toppings of your choice.