Grind the walnut with a kitchen processor until it becomes like a powder.
Prepare your food processor with the dough hook.
Add the ground walnut, powdered sugar, softened butter (room temperature), egg, lemon zest, vanilla essence and salt to the food processor and mix until everything is incorporated.
Add all the flour at once and mix briefly, until incorporated, for no more than 2 minutes. You don’t want to overmix.
Take the dough out of the food processor, wrap it with cling film, and put it in the fridge for a minimum of two hours.
Take the dough out and let it reach room temperature, for about half an hour.
Take a small piece of dough and roll it between your hands to form the crescent shape.
Place it on a baking tray lined with baking paper.
Preheat the oven to 180 degrees Celsius.
Continue until you fill the tray, then bake for 12-15 minutes.
You may need to bake in batches.
Once cooled down, sprinkle with powdered sugar.