Generously butter two 9x13" pans. Place bread into the baking dishes in a single layer.
In a large bowl whisk together the eggs, milk, sugar, salt and vanilla. Pour over the bread and cover with plastic wrap or foil and refrigerate overnight.
When ready to serve. Remove the pans from the fridge and heat the oven to 350F. Drizzle the melted butter over the bread, coating evenly. Bake for 45-50min. until the bread is puffy and lightly browned. Remove from the oven and let stand for 5 min. Serve with a dusting of icing sugar or maple syrup
Nutrition calculation is an estimation only. If you need nutritional calculations for medical reasons, please use a source that you trust.