My recent experience of cooking thawed frozen balls... best results achieved when warmed higher than room temperature before cooking. When defrosted then left 5+ hours at room temp, they came out a bit like a leavened chapati (tasting like a naan). When given a bit of a temp boost, they came out close to those freshly cooked. Basically the balls must feel to have bloated and softened before you start to cook. In my case, I sat them above the fire for a bit. Must be wrapped in cling film to prevent drying.