Soufflé à la Liqueur

Name: Soufflé à la Liqueur (Liqueur Soufflé)
Prep time: 45 min
Total time: 45 min
Yield: Serves 4
Cuisine: French
Ingredients: 250 milliliters (1 cup plus 1 tablespoon) milk; 135 grams (4¾ ounces) sugar; ½ vanilla bean; 10 grams (⅓ ounce) confectioners’ sugar, optional; 4 large egg whites; 3 large egg yolks; 20 milliliters (4 teaspoons) Grand Marnier or other liqueur; 30 grams (1 ounce) all-purpose flour, sifted; 10 grams (2 teaspoons) unsalted butter, softened