adapted from Elise Bauer's recipe on Simply Recipes
yields about 2 dozen cookies
1 cup whole pecans
3 egg whites, brought to room temperature
pinch of salt
1 cup of granulated sugar
1 tsp white vinegar
Preheat the oven to 250 degrees F. Place pecans in an oven proof dish and bake until lightly toasted, about 10 minutes. Using a blunt object, smash pecans until broken into small pieces. Set aside.
Increase the oven temperature to 300.
Add egg whites to the bowl of a stand mixer with the whisk attachment. Add salt. Whisk the eggs on low, gradually increasing the speed until frothy and soft peaks begin to form, about 2 to 3 minutes.
Increase the speed to medium-high, and slowly add the sugar 2 Tbsp at a time. Allow each addition to thoroughly combine before adding the next. Continue to whisk the eggs and sugar for a 2-3 minutes. Add the vinegar to the bowl. Increase speed to high and whisk until the mixture is glossy and stiff peaks form, 4-5 minutes.
Gently fold in the pecan pieces. Drop by heaping teaspoons onto parchment lined baking sheets.
Place the baking sheet in the preheated oven, close the door and turn the oven OFF. Leave them in the oven overnight to dry. In the morning the cookies should be crisp on the outside, but light and airy on the inside. If they are a little marshmallowy or chewy on the inside in the morning, allow them dry out for a few more hours.
Store at room temperature in an air tight container.