Make the ice cream: Place the orange juice in a large skillet or saute pan and bring to a boil over high heat. Continue to cook until juice is reduced to 1/4 cup, about 15 minutes. Set aside.

In a medium mixing bowl, combine the sugar, egg yolks and orange zest and, using an electric mixer or a whisk, beat until yolks are thickened and pale yellow. Set aside.

In a heavy medium saucepan bring the heavy cream and milk to a simmer over medium-high heat. Ladle a cup of the hot milk mixture into the egg yolk mixture and whisk to combine. Transfer the egg yolk mixture to the saucepan and whisk to combine. Reduce heat to medium-low and cook, stirring constantly, until mixture thickens slightly so that it coats the back of a spoon. Add the reserved orange concentrate to the custard, then strain the custard through a fine mesh sieve into a clean mixing bowl. Place the bowl in an ice bath and stir frequently until cooled. Transfer to the refrigerator until thoroughly chilled.

Once the custard is chilled, transfer to an ice cream machine and process according to the manufacturer's instructions. Transfer the ice cream to a freezer-safe container and freeze for at least 2 hours before serving.

Make the crepes: In a large bowl, whisk together all the ingredients except 2 tablespoons of the butter, to form a smooth, thin batter. Cover and refrigerate for 1 hour.

Heat a 6-inch crepe pan or a heavy small skillet over medium-high heat. When hot, brush lightly with some of the remaining 2 tablespoons melted butter. Ladle about 3 tablespoons of the batter into the pan, tilting it to coat evenly with batter. Cook until the crepe is golden brown on the bottom and the top is beginning to dry, 1 to 2 minutes. Using a rubber spatula, carefully turn the crepe, and cook just until the bottom colors slightly, about 30 seconds. Transfer to a plate. Repeat with the remaining batter, adding a small amount of butter to the pan for each crepe. Stack the crepes between sheets of waxed paper and set aside until ready to use.

Note: Crepes may be stacked between sheets of waxed paper, wrapped in plastic wrap and frozen for up to 2 months before using.

To make the sauce, combine the butter and sugar in a medium skillet over medium high heat and cook until the sugar is melted. Add the orange juice, 1/4 cup of the orange liqueur, and the orange zest, and heat until well blended. Fold each of the crepes into quarters. Add folded crepes, in batches if necessary, to the orange sauce. Warm the crepes until thoroughly heated. Transfer 2 crepes to each of 8 plates. Add the remaining 1/4 cup of the orange liqueur to the remaining sauce in the skillet and ignite with a match. Scoop 1 or 2 scoops of the ice cream onto the warm crepes, then pour some of the remaining sauce over the ice cream. Serve immediately.