Preheat the oven to 170°C and line two large baking sheets and two wire racks with parchment paper.

In a large bowl, use a handheld electric mixer to beat the butter with 1/2 cup of sugar at medium speed until creamy.

Add the vanilla extract and continue beating until combined.

At low speed, gradually add the flour and ground roasted cashews, mixing until incorporated.

Divide the dough onto four sheets of plastic wrap and shape each portion into logs about 3 centimeters in diameter.

Wrap the logs tightly in plastic wrap and refrigerate until firm, at least 20 minutes.

Once firm, cut the logs into 3-centimeter lengths and roll each piece into a ball.

Place the balls on the prepared baking sheets, spacing them about 7 centimeters apart.

Bake in the lower and upper thirds of the oven for 20 minutes, or until golden and set, rotating the baking sheets halfway through for even baking.

While the cookies are still warm, fill a pie plate with the remaining sugar and roll each cookie in it to coat.

Transfer the coated cookies to the parchment-lined racks to cool completely.

Once cooled, re-roll the cookies in sugar and arrange on a serving plate.