Preheat oven to 300°F. If you have two matching heavyweight, light- to medium-colored baking sheets, stack them (one inside the other) and line the top sheet with parchment paper or a silicone baking mat; otherwise line a single baking sheet.
In a large bowl, whisk together 2 cups (180g) sifted almond flour, 1 cup (200g) granulated sugar, 3 tablespoons (15g) Dutch-process cocoa powder, and a pinch of salt until evenly combined.
In a separate bowl or the bowl of a stand mixer fitted with the whisk attachment, whisk 2 large egg whites and 1/4 teaspoon lemon juice until soft peaks form.
Add the beaten egg whites and 1/2 teaspoon almond extract to the dry ingredients. Stir with a spatula or spoon until the mixture comes together into a soft, sticky dough; knead briefly with your hands if necessary to fully combine.
Place confectioners’ sugar in a shallow bowl or plate. Lightly dust your hands with confectioners’ sugar.
Using a small cookie scoop or a teaspoon, portion the dough into about 1-inch balls. Roll each portion between your hands to smooth, then roll each ball in confectioners’ sugar to coat.
Arrange the coated balls on the prepared baking sheet(s), leaving about 1 inch of space between cookies.
Bake in the preheated 300°F oven. If using the stacked double baking sheets, bake 30–35 minutes; if using a single sheet, begin checking at about 25 minutes. Bake until the tops are cracked and the bottoms are just starting to darken.
Remove the baking sheet from the oven and let the cookies sit on the sheet for a few minutes, then transfer them to a wire rack to cool completely.
Store cooled cookies at room temperature in an airtight container or bag for up to 5 days.