Combine eggs with salt, sugar, and milk, stirring well to blend; gradually add flour, stirring until smooth.

Heat a six- to seven-inch skillet over moderately high heat, greased lightly. Pour in sufficient batter to thinly coat the bottom of the pan (one to two tablespoons), quickly rotate the pan to distribute batter evenly, and pour excess batter back into bowl.

Cook until the batter sets and the edge of the pancake starts to leave the sides of the pan. Turn out onto a clean cloth and repeat until all batter is used, greasing pan when needed. Regulate the heat and frying time so that each pancake will cook to a uniform pale gold color.

In the work bowl of a food processor combine all ingredients and process until smooth.

Peel and cook potatoes.

Chop and saute onion. 

In the work bowl of a food processor, combine all ingredients until smooth; adjust seasonings.

Place a tablespoon of filling in the center of the cooked side of the pancake and fold over to make a square pocket or place filling at one end of the blintz leaf and roll up encasing the filling.

Fry the blintzes on all sides until golden.

Serve with sour cream and or fruit sauces.