Rioja style “cracked” potatoes

Patatas riojanas

“Cracked” potatoes? More than one recipe described this traditional technique favored by Spanish cooks for cutting up potatoes. Place the potato half cut side down on the cutting board; slice halfway into it near one end, then give your knife a twist. This will break off rough chunks of potato, exposing more surface, causing the potatoes to release more starch into the sauce to help thicken it. For this same reason, do not rinse the potatoes after you’ve “cracked” them, or you’ll wash away the starch.
By Tapas Together Edinburgh