Lightly beat eggs and then whisk in milk, salt and cinnamon if desired.
Melt butter in skillet over medium heat.
Dip bread slices in egg mixture until coated on both sides and then into hot skillet.
Cook over medium heat until browned on 1st side and then turn, cooking until browned on 2nd side. This usually takes about 2 minutes per side.
Notes
Depending on the size of your skillet and the size of the bread slices you may need to cook the french toast 2 slices at a time. If this is the case use 2 teaspoons of butter for every two slices.If buttermilk is unavailable, whole milk, 1% or 2% milk or skim milk can be substituted.