Preheat the oven to 350°F (180°C). Grease an 8x8–inch (20x20–cm) pan with butter or nonstick cooking spray and then line the pan with parchment paper, leaving an overhang on all sides. Grease the parchment with butter or nonstick cooking spray. Line the graham cracker sheets in an even layer on the bottom of the pan, then set it aside.
In a large bowl, whisk together the flour, Domino® Golden Sugar, cocoa powder, salt, and baking powder.
In a medium bowl, add the butter, eggs, and vanilla and whisk until well combined. Add the wet ingredients to the dry ingredients and mix until just combined. Pour the brownie batter into the prepared pan and evenly spread it on top of the graham crackers.
Bake for 30 minutes, then test the brownies by inserting a toothpick into the center of the pan; if it comes out with wet batter, the brownies are not done. If there are only a few moist crumbs, the brownies are done. Keep checking the brownies every 2 minutes until you have moist crumbs.
Remove the pan from the oven and allow the brownies to cool completely.
To Make the Marshmallow Meringue Topping:
In a large heatproof bowl, whisk together the egg whites, Domino® Golden Sugar, and cream of tartar, then set the bowl over a saucepan filled with just two inches of simmering water over medium heat. Do not let the bottom of the egg bowl touch the water. Whisk the eggs and sugar constantly until sugar is dissolved and mixture has reached a temperature of 160°F (71°C), about 4 minutes. The mixture will be thick and tacky at first, then thin out and become frothy.
Transfer the hot egg mixture to a stand mixer fitted with the whisk attachment, and add the vanilla bean paste. Beat on high speed until stiff, glossy peaks form, about 4 to 5 minutes.
Mound the meringue on top of the cooled brownies, swirling it decoratively. Serve immediately OR torch it with a kitchen torch for a delicious toasted marshmallow topping. (Do not place in the oven under the broiler– it will melt.)
The brownies, once topped with the marshmallow meringue, can be left at room temperature for up to 6-8 hours. Cover and store leftovers for up to 2 days in the refrigerator.