Start by cutting the bread slices into bite-sized cubes, roughly 1 inch in size. Set aside.
In a mixing bowl, whisk together the eggs, milk, vanilla extract, ground cinnamon, and sugar until well combined.
Heat the skillet or frying pan over medium heat and add the butter, allowing it to melt and coat the bottom.
Dip each bread cube into the egg mixture, ensuring all sides are coated, but do not soak them. Place the dipped bread into the skillet.
Cook the bread bites for about 2-3 minutes on each side until they are golden brown and crispy. You may need to do this in batches depending on the size of your skillet.
Once cooked, remove the bites from the skillet and drain any excess butter on a paper towel.
Optionally, you can place the cooked bites on a baking tray in a warm oven (about 200°F / 93°C) to keep them warm while you prepare the rest.
Serve the French toast bites warm, dusted with powdered sugar (if using), alongside maple syrup and fresh fruit for dipping.