(Makes about 36 cookies)
1 cup raw peanuts or roasted, shelled, and skinned peanuts
3 large egg whites
1 cup tightly packed brown sugar
½ cup all-purpose flour
½ tsp. kosher salt
1. Preheat the oven to 350°F.
2. If using prepared peanuts, coarsely chop the peanuts, reserve, and skip to step 3. If using raw peanuts, spread them on a large rimmed baking sheet and roast for 20 minutes, until the peanuts are fragrant and gently browned. Transfer to a colander or strainer to cool, and if the peanuts have skins, remove them.
3. Whisk the egg whites to soft peaks and fold in the brown sugar, flour, salt, and peanuts. With a teaspoon, drop the batter onto parchment-lined cookie sheets and bake until firm and gently browned, 20 minutes. Remove from the oven and with a thin metal spatula, transfer to a rack to cool. (Groundnut cakes will keep about 4 days in a sealed container at room temperature.