In a medium saucepan, combine the granulated sugar, corn syrup, and water. Stir over medium heat until the sugar dissolves completely.
Once dissolved, stop stirring and bring the mixture to a boil. Use a candy thermometer to monitor the temperature; cook until it reaches 250°F (121°C) for the hard-ball stage.
While the sugar mixture is heating, beat the egg whites and cream of tartar in a large mixing bowl using an electric mixer on medium speed until soft peaks form.
Once the sugar mixture reaches the desired temperature, carefully pour it in a thin stream into the egg whites while continuing to beat on high speed.
Continue to beat the mixture until it cools down slightly and forms stiff peaks, about 5-7 minutes. It should look glossy and hold its shape.
Gently fold in the vanilla extract, chopped candied cherries, walnuts or pecans (if using), and a pinch of salt until fully incorporated.
Line an 8x8-inch square baking dish with parchment paper, leaving some overhang for easy removal.
Pour the divinity mixture into the prepared dish and spread it evenly, smoothing the top with a spatula.
Allow the divinity to cool at room temperature for about 2-4 hours or until set.
Once set, lift the divinity out of the dish using the parchment paper and cut it into squares. Garnish with additional chopped candied cherries on top, if desired.
Notes
Arrange the squares on a decorative plate, and you can place them in paper liners for an elegant touch. Add a sprinkle of edible glitter or more candied cherries around for visual flair.