Directions

1. 1. Toast the whole almonds in a skillet over medium heat for 5-7 minutes, or until lightly golden.
2. 2. Transfer the almonds to a food processor, add 2 tablespoons of the superfine sugar, and process until finely ground.
3. 3. Beat the egg whites and salt in a large bowl with an electric mixer at medium speed until frothy.
4. 4. With mixer at high speed, gradually add the remaining superfine sugar, beating until stiff, glossy peaks form.
5. 5. Use a large rubber spatula to fold in the toasted ground almond mixture, 2 cups (300 g) finely ground almonds, cashews, and lemon and orange zests to form a stiff dough.
6. 6. Press the dough into a disk, wrap in plastic wrap, and refrigerate for 30 minutes.
7. 7. Preheat the oven to 300°F/150°C/ gas 2.
8. 8. Line four cookie sheets with parchment paper.
9. 9. Discard the plastic wrap. Roll out the dough on a surface lightly dusted with raw sugar to a thickness of 1/8 inch (3 mm).
10. 10. Use a sharp knife to cut the dough into 1 1/2-inch (4-cm) squares. Gather the dough scraps, re-roll, and continue cutting out cookies until all the dough is used.
11. 11. Transfer the cookies to the prepared cookie sheets, placing them 1 inch (2.5 cm) apart.
12. 12. Bake, one sheet at a time, for 12-15 minutes, or until just golden around the edges.
13. 13. Cool on the sheets until the cookies firm slightly. Transfer to racks to finish cooling.
14. 14. Mix the confectioners' sugar and water in a small bowl and spread over the cookies. Sprinkle with the sugar crystals.