This article examines the use of cooking vessels from Early Postclassic (AD 900–1250) Xaltocan, Mexico, through residue analysis of ceramic sherds. The analysis combined phytolith and starch analyses with Fourier transform infrared spectroscopy. Because our understanding of prehispanic foodways in central Mexico is based largely on sources that describe or depict Aztec practices in the sixteenth century, we ask how foods were similar or different prior to the Aztecs. We also seek a better understanding of how plainware vessels were used in prehispanic times. Although there is long-term continuity in the preparation of foods such as tamales and corn gruels, we find that additional foods such as tuber-based stews were prepared in the Early Postclassic. In addition, some ceramic vessels, such as comales and crude bowls, had a wider range of food preparation functions than expected.