Mix the egg dip In a shallow bowl, crack the eggs and add the milk, sugar, vanilla, cinnamon (if using), and a pinch of salt. Whisk with a fork until it's all one color and a little frothy.
Dip the bread Dip a slice of bread into the egg mix, count to two, flip it, and count to two again. Let the extra drip off. Don't soak it — a quick coat on both sides is all you need.
Cook it Melt 1 tablespoon butter in a skillet over medium heat. Add the dipped slices and cook 2–3 minutes, until the bottom is golden. Flip with a wide spatula and cook 2–3 minutes more. Add more butter between batches. (Timer: ~3 minutes)
Top and serve Stack the slices on plates. Add syrup, a dusting of powdered sugar, and berries if you like. Eat while it's warm.