In a mixing bowl, whisk together the eggs, milk, vanilla extract, brown sugar, and ground cinnamon until well combined.
Spread a generous layer of peanut butter on one side of each slice of bread.
Heat a skillet or griddle over medium heat and add a small amount of butter or oil to coat the surface.
Dip each slice of bread into the egg mixture, ensuring both sides are coated, then place the peanut butter side down on the skillet.
Cook for about 3-4 minutes on each side or until golden brown and cooked through.
Remove from the skillet and serve warm, drizzled with maple syrup if desired.