Combine the gelatin and ½ cup of the water (preferably cold) in the bowl of an electric mixer. Let this stand for 15 minutes. Meanwhile, coat a 2-quart rectangular baking dish with cooking spray. Dust the bottom and sides with confectioners’ sugar, tapping out the excess.
Combine the granulated sugar, corn syrup, salt, and remaining ½ cup of water in a small heavy saucepan. Cover and cook over medium heat until the sugar melts, 4 to 5 minutes. Uncover the pan and clip a candy thermometer to the side. Increase the heat to high and boil until the mixtures reaches 243°F on the thermometer, 10 to 12 minutes. Remove the pan from the heat.
Set the mixer on low speed and immediately beat in the hot sugar syrup. Increase the speed to high and beat until the mixture is thick, white, and tripled in volume, 12 to 15 minutes. Beat in the extracts and cinnamon.
Immediately scrape the marshmallow mixture into the prepared dish and smooth the top with a spatula coated with cooking spray. Dust the top with confectioners’ sugar and refrigerate the marshmallow, uncovered, for at least 4 hours or up to 1 day.
Run a thin knife around the edge of the pan and invert the sheet of marshmallow onto a cutting board. Oil a pizza wheel or sharp knife and cut the sheet into 1½-inch squares. Dust the marshmallows with additional confectioners’ sugar, making sure all sides are coated to prevent sticking. Store them in an airtight container for up to 1 week.
Tip: If you can, use a stand mixer here. It makes it easier to beat in all the air necessary to create light, fluffy marshmallows.