Combine granulated sugar, corn syrup, maple syrup, salt and ¾ cup (175 mL) water in a medium saucepan over medium heat. Bring to a boil and continue to cook, stirring occasionally, until mixture reaches 238°F (118°C) on a candy or instant read thermometer; it should take about 10 minutes. Set aside.

Meanwhile, using a bowl for an electric mixer, place ¾ cup (175 mL) cold water, sprinkle with gelatin and let soften for 5 minutes.

Using the whisk attachment, turn mixer to low and slowly pour cooked sugar syrup over gelatin mix. Gradually raise the speed to high and beat until mixture is very stiff; it should take about 12 minutes.

Beat in maple extract and pour or spoon whipped mixture onto a prepared baking pan, lined with parchment or waxed paper, and sprayed with cooking oil; smooth with an offset spatula. Sift approximately 1 cup (250 mL) icing sugar over top; allow to sit at room temperature for at least three hours.

After mixture has set, marshmallows can be cut with a sharp knife into desired shapes. After cutting, sift icing sugar on surface to cover. Store at room temperature for up to a week. Makes 24 servings.