• To make the wrapper batter: Combine all ingredients except butter in the carafe of a blender and blend thoroughly.
• Allow to stand for thirty minutes in the refrigerator.
• To make the filling: In a food processor, process the cheeses and sugar until smooth. If too liquid, add the flour to thicken.
• Preheat oven to 250 degrees F.
• Preferably, line a baking sheet with parchment paper, or use a non-stick baking sheet.
• To make the wrappers: Melt half the butter in an 8-inch diameter skillet, preferably a non-stick skillet.
• If no non-stick skillet is available, more butter will be required.
• Pour in enough batter just to coat the bottom of the skillet and swirl pan until it is evenly distributed.
• Cook over medium-low heat until the top is set and the bottom is golden when lifted gently with a spatula.
• Do not turn wrappers! Transfer wrappers to paper towels in one layer, golden side down.
• Repeat until all batter is used.

Tips

• To fill blintz:
• Put 3 tablespoons of the filling in the center of each wrapper, keeping the golden side down for the exterior, and fold the opposite sides of the wrapper over the filling. Fold in the ends to completely enclose the filling, forming packets, and arrange these packets, seam sides down, on the baking sheet. When all wrappers are filled and all freshly-made blintzes have been transferred to the baking sheet, cover the sheet loosely with aluminum foil. Bake blintzes until heated through, about 7 to 10 minutes.
• Optional:Serve with sour cream and sugar as toppings, and with assorted fruit jams.