3/4 cup granulated sugar, preferably superfine, divided
1 1/2 teaspoons instant coffee or espresso powder, optional
3 egg whites, at room temperature
1/8 teaspoon cream of tartar
About 2 teaspoons unsweetened cocoa powder, for dusting
2 ounces bittersweet or semisweet chocolate, cut into small pieces
Position a rack in center of oven. Preheat oven to 200 degrees. Line a baking sheet with parchment paper. Stir together 6 tablespoons sugar and coffee powder.
In a clean, dry mixing bowl, beat egg whites and cream of tartar on medium speed until soft peaks form when the beaters are lifted. On high speed, gradually add sugar-coffee powder mixture, about 1 tablespoon at a time. Mixture should stand in stiff, glossy peaks when beaters are lifted. Using a rubber spatula, fold in remaining 6 tablespoons sugar. Scrape meringue into a large pastry bag fitted with a plain 1/2-inch tip. (If you do not have a pastry bag, use a quart-size plastic food-storage bag with 1 corner snipped off.)
Pipe pointed "kisses" about 1 inch high to make mushroom stems. Do not worry if the tips bend or sag; the "mushrooms" will look more realistic that way. Pipe domes to make mushroom caps. You will need an equal number of stems and caps. Sieve a light dusting of cocoa over caps and stems; fan with a stiff piece of cardboard (or use puffs of air from a clean turkey baster) to blur the cocoa and give the mushrooms an authentic look. Bake until crisp and completely dry, 2 hours.
To assemble mushrooms, place chocolate in a small bowl; set in a skillet of barely simmering water. Immediately turn off heat and stir chocolate until melted and smooth. Use a sharp knife to cut 1/4 to 1/2 inch off the tip of each stem, to create a flat surface. Spread a generous coating of melted chocolate over the flat side of several mushroom caps.
Allow chocolate to set partially before attaching the cut surface of the stems. Repeat until all of the mushrooms are assembled. Set assembled mushrooms aside until chocolate has hardened and caps and stems are glued together, about 1 hour. Meringue mushrooms may be made 3 to 4 weeks in advance and stored at room temperature in an airtight container.
Yield: 40 cookies.
Tester's note: Most will not believe how amazingly easy this cookie is to make. A great light, airy cookie, this is a beautiful addition to holiday cookie trays.
Adapted from "A Year in Chocolate: Four Seasons of Unforgettable Desserts," by Alice Medrich ($25.95, Warner Books, 132 pages).