Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: When the Prophet (peace and blessings be upon him) broke his fast, he would say: "For You I fasted and with the provision You gave I broke my fast, so accept (this fast) from me; indeed You are the All-Hearing, the All-Knowing."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12666