MAKE WRAPPER BATTER: In a blender blend wrapper batter ingredients and let stand 30 minutes.
In an 20 cm skillet, preferably nonstick, melt half of the butter over moderately high heat.
Pour in enogh batter to just coat bottom of skillet, swirling and cook, undisturbed, until top is set and nottom is golden (do not turn wrapper over.) Transfer wrapper to paper towels in one layer, golden side down. Make more wrappers with remaining butter and batter.
MAKE FILLING: In a food processor blend cheeses, sugar, and cinnamon until smooth. If necessary, add flour to thicken filling.
Preheat oven to 120ºC and line a baking sheet with parchment paper.
Put 3 tablespoons filling in center of each wrapper and fold opposite sides of wrapper over filling until sides barely touch. Fold in ends to completely enclose filling, forming packets, and arnage, seams sides down, on baking sheet.
Make more blintzes with remaining filling and wrappers. Bake blintzes, covered loosely with foil, untl heated through, 5 to 10 minutes.