Performing One Sajdah as Sajdah Sahw instead of Two

Q: Salaah-245: The Imaam made a mistake during the Fajr salaah. He Then proceeded perform the Sajdah Sahw but instead of two Sajdahs, he made only one before reciting the Tashahhud, Durood and du'aa. Is the salaah valid? Please reply with references from the books of jurisprudence.

Answer: It is Waajib (compulsory) to perform two Sajdahs as Sajdah Sahw. One will not suffice. The salaah therefore needs to be repeated. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2