2 tablespoons confectioners' sugar, or as needed (Optional)
Instructions
Melt butter in a large skillet over medium-high heat.
Whisk milk, eggs, sugar, vanilla extract, cinnamon, and allspice together in a large bowl. Dip each slice of bread into egg mixture to coat.
Place coated bread into skillet and cook until golden brown on 1 side, about 1 minute. Flip and continue cooking until second side is golden, about 1 minute more. Remove to a plate and repeat with remaining bread slices.
Sift confectioners' sugar over top of the French toast, slice diagonally, and serve.