Butter the sides of a 2-quart souffle dish and sprinkle with sugar. To make a collar for the souffle dish, measure enough foil to wrap around the top of the souffle dish and add 3 inches. Fold the foil in thirds lengthwise. Lightly butter 1 side of the foil and sprinkle with sugar. Attach the foil, sugar side in, around the outside of the dish so the foil extends 2 inches above the dish. Tape or pin the ends of the foil together; set aside. Adjust the oven rack to the lowest position.

In a small saucepan, heat half-and-half and vanilla bean (if using) until bubbles form at the edge of the saucepan. Remove from heat. Remove vanilla bean; let cool for 5 minutes. Using a paring knife, slit vanilla bean lengthwise. Scrape out seeds. Stir seeds (or the 1 tablespoon vanilla, if using) into half-in-half.

In another small saucepan, melt the 1/4 cup butter. Stir in the flour. Add half-and-half mixture. Whisk over medium heat until thickened and bubbly. Remove from heat (mixture will be thick). Gradually whisk the mixture into the beaten yolks; set aside.

In a large mixing bowl, beat egg whites and the 1 teaspoon vanilla with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add the 1/2 cup sugar, about 1 tablespoon at a time, beating on medium-high speed until stiff peaks form (tips stand straight).

Gently fold the egg yolk mixture into the egg white mixture. Spoon mixture into the prepared souffle dish. Place souffle dish in a 15x10x1-inch baking pan. Bake in a 350 degree F oven 40 to 45 minutes or until a knife inserted near center comes out clean. Serve at once with Quick Vanilla Custard Sauce. If you like, garnish each serving with a fresh mint sprig. Makes 6 servings.

Allow 1-1/2 cups good-quality vanilla bean ice cream to soften, covered, in the refrigerator about 3 hours to become of pourable consistency. When ready to serve over hot souffles, stir in 1/4 teaspoon vanilla. Makes about 1 cup.