With a whisk, beat eggs and milk together and add the salt. Gradually, a tablespoonful at a time, whisk in flour and beat until smooth. Heat a 6inch skillet and butter it lightly. Pour in enough batter to make a thin pancake. (If batter is too thick, add water to thin) Pour out excess back into the batter and don't worry if a "tab" forms on the side of the pan.
Cook the blintz on one side only until the top blisters and it looks dry around the edges. Turn the blintz upside down onto a clean towel. Rebutter the skillet if need be, every 2 or 3 blintzes, and proceed until all the batter has been used up.
Make assorted fillings, roll up and fry, or bake or freeze for another day.