Heat 10-inch skillet, grease lightly with oil. Pour enough batter to make a very thin pancake, tipping pan to cover bottom completely (like making a crepe). Cook until underside is lightly browned and top appears dry. Flip onto a sheet of wax paper, browned side up. Cover with another sheet of wax paper and make next blintz. Remember to cover each with a sheet of wax paper before stacking.
Place a heaping tablespoon of filling in center of each pancake, fold from both sides, then like an envelope. Just before serving, fry filled blintzes on both sides in a combination of butter and oil or arrange in a well greased oven proof container and bake at 400 degrees until golden brown. Serve with jelly, sour cream, fresh fruit. Makes 7-9 large.