Step 1

For batter, combine milk and egg in a blender; cover and process until blended. Add flour; cover and process until blended. Refrigerate, covered, 1 hour.

Step 2

Preheat oven to 350°. Heat a lightly greased 8-in. skillet over medium heat. Stir batter. Pour 1/4 cup batter into center of pan. Quickly lift and tilt pan to coat bottom evenly. Cook until top appears dry; turn crepe over and cook until bottom is cooked, 15-20 seconds longer. Remove to a wire rack. Repeat with remaining batter, greasing pan as needed.

Step 3

Place 6 asparagus spears on 1 side of each crepe; roll up. Place in a greased 11x7-in. baking dish. Bake, uncovered, until heated through, 10-15 minutes.

Step 4

In a saucepan, whisk egg yolks and water. Cook over low heat, stirring constantly, until mixture is thickened and coats the back of a metal spoon and a thermometer reads at least 160°. Whisk in the butter, lemon juice, salt and cayenne. Pour over warm crepes; sprinkle with paprika. Serve immediately.