Dough: Place the flour, ground almonds, sugar, cubed butter and vanilla extract in a food processor or stand mixer. Mix shortly until the dough starts to come together.
Refrigerate: Turn the dough onto the working surface and press together into a disc. Don't knead; work quickly. Divide the dough into three parts, and form each piece into a thick roll, about 2.5 cm/ 1 inch thick.Wrap each roll in cling film/plastic wrap and refrigerate for about 2 hours. The dough can be refrigerated for longer (overnight) as well.
Preheat the oven to 180 degrees Celsius/ 350 degrees Fahrenheit (fan oven 160 degrees Celsius/ 320 degrees Fahrenheit). Line two baking trays with parchment paper.
Cut the dough rolls into slices, about ¾ cm/ 0.3 inches thick. Place the pieces on the baking trays and gently press down with a fork on the top of each cookie to make a small criss-cross pattern.
Bake: If using a fan oven, you can bake both cookie trays simultaneously. If using a conventional oven, bake the cookies one tray after another. Bake the cookies for about 12-15 minutes or until slightly golden.
Leave to cool completely on the baking trays. Sprinkle with icing sugar before placing them into airtight containers.