If Someone Finishes the Tashhahud and Then Remembers that He Only Prostrated Once, What Should He Do?
by The Albaani Blog
Questioner: If someone finishes the tashhahud and then remembers that he only prostrated once, what should he do?
Al-Albaani: He carries out the second prostration and then reads the tashahhud again and after that does the prostrations of forgetfulness [sujood as-sahw].
Al-Hudaa wan-Noor, 96.