Directions

1. Preheat oven to 250 degrees and line a baking sheet with parchment paper.
2. With an electric mixer on low speed, beat egg whites with pinches of salt and cream of tartar until foamy. Increase speed to medium-high and add ¾ cup sugar, one tablespoon at a time. Combine remaining sugar with cornstarch. Gradually add sugar/cornstarch mixture and continue beating until stiff glossy peaks form, about 5 minutes. Beat in vinegar and vanilla until combined.
3. Spread the meringue onto the parchment, creating 6 circles with slightly concave centers. Sprinkle with chopped pistachios. Bake for hour and 15 minutes; then turn off the heat. Prop oven door open with a wooden spoon and cool meringues in oven at least one hour.