springy, fluffy marshmallows

INGREDIENTS

• About 1 cup confectioners’ sugar
• 3 1/2 envelopes (2 tablespoons plus 2 1/2 teaspoons) unflavored gelatin
• 1 cup cold water, divided
• 2 cups granulated sugar (cane sugar worked just fine)
• 1/2 cup light corn syrup
• 1/4 teaspoon salt
• 2 large egg whites or reconstituted powdered egg whites
• 1 tablespoon vanilla (alternately: 1/2 of a scraped vanilla bean, 2 teaspoons almond or mint extract or maybe even some food coloring for tinting)