It should be stressed that one is recommended to make up for the days missed as soon as possible. Fasting the missed days of Ramadan takes priority over optional or recommended fasting. However, it is permissible, according to some scholars, to formulate a double intention of performing recommended or optional fasts while making up for the missed ones.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states the following: If you miss Ramadan fasting, your first priority is to make up for the missed fasts. After having done so, you can fast the recommended or optional ones as you please. One of the principles of Islam, as stated by the first caliph, Abu Bakr (may Allah be well pleased him), is “Allah does not accept voluntary deeds unless the obligatory ones are fulfilled.
However, there are some scholars who are of the view that while making up for the missed fasts, you may also make the double intention of performing recommended ones. Allah is Infinitely Merciful. It is therefore befitting us, His servants, to knock at the door of His mercy, hoping that He will never turn us away. May Allah inspire us to draw nearer to Him in every possible way. Ameen.