1 teaspoon vanilla bean paste (or pure vanilla extract, or the seeds of 1 vanilla bean)
1 teaspoon white wine vinegar
1 cup confectioner’s sugar
food coloring (optional)
Preheat oven to 300 degrees F. Line a large baking sheet with parchment paper or a Silpat.
In a bowl of a stand mixer fitted with the whisk attachment, beat the egg whites to stiff peaks. Continue whisking and add the superfine sugar gradually, about 1 tablespoon at a time, allowing the sugar to completely incorporate between additions. The mixture should feel smooth, not gritty, when you rub it between your fingers. Continue mixing as needed until mixture is smooth and sugar has dissolved completely. Beat in vanilla, vinegar, and food coloring. Continue beating until smooth and glossy.
Gently fold in the confectioner’s sugar with a silicone spatula. Using a piping bag with a large fluted pastry tip, pipe the mixture onto the prepared baking sheet, leaving two inches between each meringue. (Be sure to fill the piping bag in batches, and be careful not to squeeze or stir the meringue mixture too much–you don’t want to deflate it.)
Place baking sheet on the middle rack of the preheated oven and turn the heat down to 275 degrees F. For gooey centers: Bake for 45 minutes then turn oven off and leave door closed for 15 more minutes before removing to cool. For firm centers: Bake for 60-70 minutes until baked through.
Allow to cool completely, then store in an airtight container for up to 5 days.