Flourless Fudge Cookies

Name: Flourless Fudge Cookies
Yield: about 16 cookies
Cuisine: United States
Ingredients: 255 g confectioners' sugar; 85 g Dutch-process cocoa powder; 1 tsp espresso powder; ½ tsp kosher salt (or half as much table salt); 3 large egg whites, at room temperature (about 106 g); 2 tsp vanilla extract; 170 g bittersweet chocolate chips or chopped chocolate

Also called flourless chocolate cookies, chocolate chewies

Deep, dark, brownie-edged cookies with crackly meringue tops, made with no flour and no added fat.

Makes: about 16 cookies

Cookies Gluten-free Freezes well

Adapted from King Arthur Baking

Ingredients

Scale

Amounts are for the recipe. Sizes, times and temperatures in the method are not scaled.

255 g2¼ cupsconfectioners' sugar
85 g1 cupDutch-process cocoa powder
1 tspespresso powder
½ tspkosher salt (or half as much table salt)
3large egg whites, at room temperature (about 106 g)
2 tspvanilla extract
170 g1 cupbittersweet chocolate chips or chopped chocolate

Amounts worked out from the other system are rounded.

Method

Prepare the pans. Line two sheet pans with parchment and grease the parchment with spray or a thin film of oil. The batter is like meringue and welds itself to bare paper.
Sift the dry ingredients. Sift the confectioners' sugar (255 g2¼ cups) and cocoa powder (85 g1 cup) through a fine sieve into a large bowl, then whisk in the espresso powder (1 tsp) and salt (½ tsp). Sifting matters, because cocoa clumps won't break up later.
Add most of the whites. Whisk the egg whites (3) and vanilla (2 tsp) together in a small bowl. Pour about three quarters into the dry ingredients and stir with a stiff spatula until just moistened. Add the rest a splash at a time, until the batter falls from the spatula in a thick, slow ribbon, like warm hot fudge and not like pancake batter. Stop as soon as you get there.
Fold in the chocolate. Stir in the chocolate chips (170 g1 cup).
Scoop and rest. Scoop 2-tablespoon mounds onto the pans, at least 3 inches apart, no more than 8 or 9 to a sheet. Let them sit at room temperature for 30 minutes while the oven heats to 350°F. The rest is what produces the crackled top.
Bake one sheet at a time for 11 to 13 minutes, until the tops are glossy, puffed and cracked and the edges look matte and set. The centers stay soft. A cookie that won't release was pulled too early.
Cool completely on the pan. Don't move them while warm. Once they are fully cool, slide a thin metal spatula flat and fast under each cookie.

Notes

Weigh the confectioners' sugar and cocoa. Both compress a lot, and there is no flour or butter to absorb an error.
Egg whites. Brands of confectioners' sugar carry different amounts of cornstarch, which is why the whites go in gradually.
Chocolate. The chips push these toward brownie. Leave them out for a thinner, crisper cookie.
If the batter is too runny, resting won't fix it. Sift together confectioners' sugar and cocoa, 3 to 1 by weight, and stir it in 25 to 30 g at a time until the batter ribbons, with a pinch of salt and ¼ tsp espresso powder. A teaspoon or two of cornstarch is a quicker fix if you don't want more sweetness; past 2 tsp you taste it.
Or bake it runny for thin, wide, crackly wafers: scoop smaller, space them 4 inches apart and bake a couple of minutes longer. Either way, bake a couple of spoonfuls as a test first.
Cocoa. Dutch-process is rounder and darker, natural sharper and fruitier. Both work, since there is no leavening.
If they come out too crisp, leave them uncovered on parchment overnight and they soften to chewy.
Freezing. Freeze the baked cookies, not the batter; they keep 2 to 3 months. Thaw them uncovered at room temperature. The dry ingredients can be sifted together ahead and stored airtight. Don't refrigerate the batter overnight, because it turns to putty.