Preheat oven to 335. Line an 8” square pan with parchment paper.

Make the brownie batter: Over a double boiler (or a heatproof bowl over simmering water – with the water not touching the bowl) add the butter. Once the butter melts add the cocoas and sugar, cook while stirring until the temperature reaches 140 F and at that point, remove from the heat.

While the brownies are baking, add the egg whites and sugar to a bowl and whisk. Set over a double boiler (or a heatproof bowl set over a pot with simmering water, without the water touching the bowl) whisk together the mixture constantly until it is frothy and no sugar granules can be felt when you rub the meringue between your fingers.

Using a hand mixer or stand mixer, beat the meringue until it is thick, shiny and holds fairly stiff peaks. When the meringue is almost done beating, add the vanilla, salt, cornstarch and vinegar to blend it in. Fold in ground oreos gently and in big streaks (you only need to do 3-5 folds).

When the brownies reach the 20 minute mark, remove from oven and let cool for 5 minutes. Gently dollop the meringue on top of the brownie (it will puff and spread so don’t worry about getting it to the edges). Return to oven and bake for another 25 – 30 minutes. It’s done when the meringue is dry to the touch and the mix doesn’t jiggle when you shake it. Allow to cool fully before slicing and serving.