Mishkat al-Masabih 3142
She said:
“God’s Messenger married me in Shawwal and cohabited with me in Shawwal, so which of the wives of God’s Messenger was more beloved by him than I?" 

Muslim transmitted it.
وَعَنْهَا قَالَتْ: تَزَوَّجَنِي رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي شَوَّالٍ وَبَنَى بِي فِي شَوَّالٍ فَأَيُّ نِسَاءِ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ أَحْظَى عِنْدَهُ مِنِّي؟ . رَوَاهُ مُسلم