1. Preheat oven to 200 degrees Fahrenheit (90 degrees Celsius). Using a four-inch (10-centimeter) bowl or round
cookie cutter, trace six circles on each of two sheets of Gefen Parchment Paper. Transfer each sheet of paper to a baking sheet, tracing-side down.
2. In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites with a pinch of salt on high speed until soft, glossy peaks form. With the mixer running, add sugar gradually. Beat until stiff and glossy, about three to five additional minutes. Sprinkle in cornstarch, vinegar, and vanilla; fold gently to combine.
3. Using two spoons, scoop a mound of meringue into the center of each of the circles. Use the back of one spoon to create an indentation in the center of each mound. Alternatively, you can pipe the meringue into cup shapes
using a pastry bag with an extra-wide star tip.
4. Drizzle each cup with the melted chocolate in a zigzag pattern and place the baking sheets into the oven. Bake for two hours, until firm and dry to the touch but not browned. Turn off oven and let pavlovas cool for one hour.
Transfer to a wire rack to cool completely.
5. Once the pavlovas have cooled, prepare the ganache by heating up the pareve whipping cream in a small saucepan until it reaches a gentle simmer. Remove from heat and add the chopped chocolate. Whisk together until thick and creamy. Spoon one to two tablespoons of the ganache into the hollow of each cup, spreading to coat. Allow to cool and set completely for at least two hours before topping with peanut butter mousse.
6. To make the peanut butter mousse, beat the pareve whipping cream, confectioners’ sugar, and vanilla extract until it forms stiff peaks. Heat peanut butter in the microwave for 15–20 seconds until runny. Gently fold into the whip until no streaks remain.
7. Transfer the mousse to a piping bag. If the mousse is too runny, refrigerate for one hour in the piping bag. Pipe mousse over the chocolate ganache in each meringue cup to form a swirl shape. Top with peanut brittle crunch to garnish. Refrigerate loosely covered until ready to serve, up to two days.