1. In a wide, shallow bowl, beat the eggs, milk, vanilla, cinnamon, and salt together with a fork until well-combined. Place the slices of bread in the custard and gently press them down to help the bread absorb the custard, then turn them over the do the same to the other side of the bread.
2. Heat a good-sized pat of butter in a large skillet over medium heat. Add the custard-soaked slices of bread to the pan and cook until they’re browned on the bottom, about a minute. Turn the slices of bread over and fry on the other side until browned on the bottom.