Step 1

PreparationMake crêpes In blender, combine milk and eggs. Add flour and salt and blend at low speed until smooth, less than 1 minute. Let batter stand 1/2 hour.

Step 2

Have ready large plate or platter. Place skillet over moderately high heat, brush lightly with some melted butter, and heat until butter just begins to smoke. Pour 1/4 to 1/3 cup batter into pan, tilting to spread into thin, even layer. Cook until crêpe begins to "blister," edges curl slightly away from skillet, and underside is lightly browned, about 1 to 2 minutes. Use flexible spatula to flip crêpe out of skillet and onto plate, cooked side up.

Step 3

Repeat with remaining batter, brushing skillet lightly with melted butter before cooking each crêpe. Stack crêpes, cooked side down, on plate and let cool.

Step 4

Make filling In large bowl, mash together farmer and cottage cheeses until blended. Add egg yolk, melted butter, sugar, and salt, and mix until combined.

Step 5

Place 1 crêpe, cooked side up, on a plate. Place 2 tablespoons filling in center, and fold up bottom to cover filling. Fold down top, then flip over and fold in sides. Flip over again and place on a large plate. Repeat with remaining crêpes and filling. (Can be made up to 1 day ahead; cover and chill until ready to fry.)

Step 6

Make sauce In large saucepan, combine 3 cups blueberries, sugar, and cornstarch. Set over moderately low heat and stir gently until sugar dissolves. Raise heat to moderately high and boil, stirring occasionally, 3 minutes. Remove from heat and gently stir in remaining blueberries.

Step 7

Fry blintzes Heat 1 tablespoon butter in iron skillet over moderately high heat. Add 3 blintzes and fry until golden brown on both sides, about 1 to 2 minutes per side. Repeat with remaining blintzes. Serve hot with sauce.