1 1/2tspcoffee extractSubstitute: 1 tsp pure vanilla extract
1 3/4cupspistachiosSubstitute: 1 1/2 cups pecans
Preheat oven to 200 degrees. Combine egg whites and sugar in a bowl set over a saucepan of simmering water, and whisk until sugar is dissolved and mixture is warm, about 3 minutes. Whisk in salt and cream of tartar; remove from heat.
Beat mixture with an electric mixer on medium-high speed until stiff, glossy peaks form and meringue is mostly cooled, about 7 minutes. Beat in extract.
Fit a pastry bag with a 3/8-inch round tip (Ateco #804) and fill bag with meringue. Pipe meringue "kisses," each 1 inch in diameter, releasing pressure and pulling pastry bag straight up to create each, 1 inch apart on parchment-lined baking sheets. Bake until crisp on outside and able to release easily from parchment, about 1 hour, 15 minutes. Transfer to a wire rack and let cool completely.
Melt chocolate in a bowl set over a saucepan of simmering water, stirring until smooth; remove from heat. Working 1 at a time, dip base of each meringue in chocolate, then coat base completely with nuts. Transfer to parchment-lined baking sheets and let stand until set, about 1 hour. Meringues can be made 5 days ahead and stored in a cool, dry place at room temperature.