Preparation

• Crêpe batter:
  In a mixing bowl, whisk together the flour, eggs and milk until the batter is smooth. Stir in the cool melted butter and orange zest. Let the batter rest for 30 minutes.
  Heat a 7-inch nonstick pan until a drop of water will sizzle on it. Then ladle in 2 ounces of the batter, tilting the pan to coat the bottom. Cook the crêpe until golden brown (check the color by lifting the edges of the crêpe with a metal spatula). Then flip it with the spatula and cook the other side. Transfer to a plate and set aside. Continue cooking the other crêpes. Stack the crêpes as they are made.
  Pastry cream:
  In a heavy-bottomed saucepan, bring the milk to a boil. In a mixing bowl, whisk the egg yolks and sugar until light and creamy. Add the flour, cornstarch and vanilla. Mix well. Pour the scalded milk over the egg yolk mixture, and whisk well to blend. Return the mixture to the saucepan. Bring to a boil, while whisking constantly. Reduce the heat and simmer 5 minutes, whisking to reach all parts of the pan.
  Transfer the pastry cream to a mixing bowl. Mix in the vanilla extract and Cointreau. Cover with a film wrap to prevent a crust from forming. Let cool.
  Preheat the oven to 350 degrees F. Beat the egg whites and the cream of tartar with an electric mixer until stiff peaks form.
  Whisk 1/3 of the egg whites into the pastry cream mixture to loosen it; fold in the remaining egg whites.
  Line 8 crêpes on a working surface. Divide and spoon the soufflé filling on one-half of the crêpes and fold the opposite side over.
  Bake until the crêpes have risen and puffed, about 10 minutes. to serve, transfer the crêpes to individual hot plates. sift confectioner's sugar over each crêpe. Serve immediately.