Nutrition per serving may change if servings are adjusted.
1/3 cup all-purpose flour
1/3 cup buckwheat flour
3/4 cup low-fat milk
2 tablespoons sugar
1 large egg
2 large egg whites
2 teaspoons canola oil
1 teaspoon vanilla extract
1/8 teaspoon salt
1 1/4 pounds rhubarb, trimmed and cut into 1/2-inch pieces (5 cups)
3/4 cup sugar
2 tablespoons all-purpose flour
1 teaspoon freshly grated orange zest
2 tablespoons orange juice
1 tablespoon butter
Confectioners' sugar, for dusting
Strips of orange zest, for garnish
To make crepe batter: Combine 1/3 cup all-purpose flour, buckwheat flour, milk, 2 tablespoons sugar, egg, egg whites, oil, vanilla and salt in a food processor; process until smooth. Transfer the batter to a bowl, cover and refrigerate for at least 30 minutes.
To make filling: Combine rhubarb, 3/4 cup sugar, 2 tablespoons flour, orange zest, orange juice and butter in a saucepan and stir over medium-low heat until the rhubarb is tender and the juices are thick, 10 to 15 minutes. Remove from the heat and set aside.
To cook crepes: Rub an 8-inch nonstick skillet or seasoned crepe pan with an oiled paper towel and heat over medium-high heat until a drop of water dances on the surface. Ladle a scant 2 tablespoons crepe batter into the pan and tilt to coat the bottom evenly. (If the batter is too thick to readily coat the pan, stir in a little more milk.) Cook until the underside is brown, 30 to 45 seconds. Loosen the crepe with a spatula, and quickly turn it over with your fingertips. Cook until the bottom is lightly browned, 20 to 30 seconds. Transfer to a plate. Repeat with the remaining batter, rubbing the pan with oil between crepes. Stack the crepes as they are cooked. (You will have about 14 crepes.)
To assemble and bake crepes: Preheat oven to 375 °F. Coat a shallow baking dish with cooking spray. Spread about 2 tablespoons of the rhubarb filling in the center of each crepe. Fold in quarters and set the crepes in the prepared baking dish. Bake, uncovered, until heated through, 10 to 15 minutes. Serve dusted with confectioners' sugar and garnished with strips of orange zest.
Make Ahead Tip: The filling (Step 2) can be prepared ahead and stored, covered, in the refrigerator for up to 4 days. The crepes (Step 3) can be prepared ahead and stored, covered, in the refrigerator for up to 2 days.