01 - Preheat the oven to 250°F. Line two baking sheets with parchment paper.
02 - In a clean, dry mixing bowl, beat the egg whites and cream of tartar using an electric mixer on medium speed until foamy.
03 - Gradually add the sugar, 1 tablespoon at a time, while beating on high speed. Continue beating until stiff, glossy peaks form (about 6-8 minutes).
04 - Beat in the salt, vanilla, and peppermint extract until just combined.
05 - Gently fold in the chopped dark chocolate and mint chips with a spatula.
06 - Using two spoons or a piping bag, drop or pipe mounds of meringue (about 2 tablespoons each) onto the prepared baking sheets, spacing them about 1 inch apart.
07 - Bake for 60 minutes, then turn off the oven and let the meringues cool inside, undisturbed, for another 30 minutes to dry out.
08 - Remove from the oven and let cool completely on the baking sheets before serving or storing.