GrizShel,
I fly the first leg DCA-MSP every other week, and you're right you get a choice of cold cereal, yoghurt and a bagel. You're problem is you need to fly a bit further, i.e. the West Coast, then you get a hot breakfast...or as a 2nd choice the famous cold breakfast. It has to do with miles flown and time of day, etc.
WinkDaddy provided this link.
First class:
https://www.delta.com/traveling_chec....../dining.jsp