Is reciting the Salawat upon the Prophet (peace be upon him) ten times after the supplication "Allahumma ij'al fi qalbi nooran..." when going to the mosque considered an innovation (bid'ah)? And if so, should it be left without a specific number, or should one be content with the supplication only?

Allah Almighty commanded His servants to invoke blessings upon the Prophet, peace and blessings be upon him, and many hadiths have been reported regarding its virtues. Among them is that whoever invokes blessings upon him once, Allah will invoke ten blessings upon him in return. Your invoking blessings upon the Prophet, peace and blessings be upon him, with the mentioned number, is legislated and recommended. Specifying a number is not prohibited, but it should not be adhered to as a Sunnah because no specific number has been reported. Adhering to a specific number for general adhkar is considered an additional innovation (bid'ah idafiyyah). Increasing the invocation of blessings upon the Prophet, peace and blessings be upon him, is legislated at all times, especially on Friday.