Melt the butter in a cast iron skillet on medium heat.
Whisk together all other ingredients except the bread. (Because why would you whisk bread?)
Soak two bread slices in the egg mixture for 5 to 10 seconds per side, letting the bread absorb some of the liquid.
Add the soaked slices of bread (in a single layer) to the cast iron skillet and cook for 2 minutes on the first side. Flip, cover the skillet with a lid, and cook another 2 minutes. (Covering with a lid helps you trap some steam in order to fully cook the inside of the toast while you brown the outside.)
Repeat the process with the rest of the bread. Depending on how dry and absorbent your bread is, you should get 4 to 6 slices out of this recipe.
Top with maple syrup & fruit as desired, and serve immediately.