Perfect Homemade Marshmallows {made without corn syrup}

Bahan-bahan (96 porsi)

• 1 cup powdered sugar
• 3 tablespoons unflavored gelatin (about 3 1/2 envelopes)
• 1 cup cold water (divided)
• 2 cups granulated sugar
• ½ cup brown rice syrup (or corn syrup) (or an additional 1 cup sugar and ¼ cup water)
• ¼ teaspoon kosher salt
• 2 large egg whites
• 1 vanilla bean (scraped or 1 tablespoon vanilla)