Instructions: In a medium saucepan, combine granulated sugar and water. Bring to a boil over medium-high heat, stirring until the sugar dissolves. Once boiling, stop stirring and let it cook until it reaches 240F soft-ball stage on a candy thermometer. While the sugar syrup is cooking, beat the egg whites in a clean, dry bowl until they become frothy. Add the cream of tartar and continue to beat until stiff peaks form. Once the sugar syrup reaches 240F, remove it from the heat. Slowly pour the hot syrup into the beaten egg whites while continuing to beat at medium speed. Be careful not to pour it onto the beaters. Add the lemon juice, lemon zest, vanilla extract, and a pinch of salt to the mixture. Continue beating until the marshmallow fluff becomes glossy and thick, about 5-7 minutes. If desired, add a few drops of yellow food coloring to achieve the desired lemony color and mix until well incorporated. Transfer the Lemon Marshmallow Fluff to a piping bag fitted with a large star tip or a plastic bag with the corner snipped off. Pipe the fluff onto a parchment paper-lined baking sheet in small swirls or dollops. Allow the marshmallow fluff to set at room temperature for about 2-3 hours, or until it's no longer sticky to the touch. Once set, dust the marshmallow fluff with powdered sugar and use a kitchen torch to lightly brown the tops for a toasted effect. Serve your Lemon Marshmallow Fluff on its own, as a topping for desserts, or use it in your favorite recipes. Enjoy!