It is called the Restoran Berputar Seri Angkasa. It is on top of the Menara Tower.
When I last went there the food was nothing special, but the views are worthwhile.
Oh yes - - the machinery was obviously a bit iffy that night because the soup had a wave motion on it as the rotation slowed slightly every 4 to 5 seconds - - - - you could feel the hesitation.
Having seen how buildings were put up in KL over about 3 years, we didn't hang around long after eating.
Also in my opinion, KL is one of the best cities for simply sitting and "people watching" in the evening.