Super Junior-H is Super Junior's fourth official sub-unit after Super Junior-K.R.Y, Super Junior-T, and Super Junior-M. They debuted on 7 June 2008 with the performance of their first promotional dance single, "Cooking? Cooking!", at the 2008 Dream Concert. Their EP contains a total of five tracks, all of which display exhilarating music with cheerful dances, bringing happiness to listeners. Bubbly and blissful with playful and chatty lyrics, the title track "Cooking? Cooking!" is widely known to be reserved as the "Best Summer Song of the Year" by SM Entertainment. The lyrics deal of a fun episode that took place while eating the food a girlfriend cooked. Other tracks, such as "Pajama Party", "You&I", and "Sunny" are other samples of the same bubbly genre, however, each song differ in style because of the unique sounds that are incorporated into each different track. "You&I" is influenced by modern jazz/swing music while "Sunny" is an influence from retro, disco dance. The last track, "Good Luck!!" is a medium-tempo ballad with vocal harmonization, which also includes a brief a cappella performance by the members.
The EP's jacket photoshoots are also included in the album, compressing them into a 28-page long booklet. The themes of the photoshoots contain a variety of different themes, such as a fun pajama party, a pillow fight, and a cooking party.