CREPE BATTER: 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 6” 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.
Re-butter the skillet if need be, every 2 or 3 blintzes, and proceed until all the batter has been used up.
FILLING: Completely defrost the spinach and squeeze out any excess liquid. Add the butter or olive oil to a skillet and saute the scallions about 2 minutes. Add the spinach and continue to cook about 5 minutes longer.
Add the sesame oil and cheese folding the spinach over the cheese until it melts. Season with salt and pepper. Remove the filling from the pan and cool before stuffing your blintz crepes.
ASSEMBLY: Place 2 tablespoons of filling in center of crepe. Fold bottom over filling. Fold sides over filling. Fold top over filling and roll till sealed.
Place in lightly greased saute pan, seam side down. Brown for 3-4 minutes on each side till lightly browned. Serve warm with a dollop of sour cream.