Authentic Supplication Number 210.

When the Messenger of Allah  would break his fast he would say: Thahaba ‘ath-thama’u wabtallatil-`urooqu wa thabuta ‘al-‘ajru ‘in sha’a ‘allahu (226).

Footnotes.
(226) The thirst is gone, the blood vessels have become moist, and the reward has been established with the Will of Allah.

Reporters.
‘Al-Albani, ‘Al-Hakim, ‘Al-Bayhaqi, ‘Ath-thahabi have said it was sound. ‘Al-Hakim and ‘Ath-thahabi said it was sound according to the conditions of Al-Bukhari, and Al-Bukhari and Muslim respectively. Al-Daraqutni reported it on page 185 of volume 2, and he said that ‘Al-Hussein bin Waqid, a person in the chain, was a sole reporter for it, and that the hadeeth’s ascription was comely. Al-`Adawee said it was comely.