Preheat the oven to 350F (180C).
Grind the walnuts in a food processor. It takes just a few seconds. It should resemble coarse sand or almond flour. Be careful not to turn it into walnut butter. Set aside.
200 grams walnuts
Place a heatproof bowl over simmering water. Make sure the water doesn’t touch the bowl. Add the egg whites and beat with a hand mixer until foamy.
2 egg whites
Add the sugar and beat for two more minutes until soft peaks form. Remove from the heat.
150 grams granulated sugar or caster sugar
Fold in the ground walnuts, a pinch of salt, vanilla extract, and cornstarch. Cover with a lid or plastic wrap and place in the fridge for 1-2 hours, or up to 24 hours.
Pinch of salt, 1-2 teaspoons vanilla extract, 10 grams cornstarch
Using a cookie scooper or a spoon, scoop each cookie and place it on a parchment paper-lined tray, about 2 inches apart.
Bake on the middle rack for 12-14 minutes, until crackly and golden. Remove from the oven, let them rest and firm up for a couple of minutes before transferring them to a wire rack to cool completely. Enjoy!