The chemical composition of an extrasolar planet is a fundamental property with few observational constraints. Spectroscopic observations of polluted white dwarfs have proven to be a successful pathway to measure the compositions of disrupted planetesimals, but this approach has its own limitations. Here, we present results from a new method to measure the compositions of extrasolar planets by modeling the gas debris around polluted white dwarfs. These disks are fresh extrasolar planetary material in a transient stage, right after tidal disruption and before being completely accreted onto the white dwarf. Recent increases in the sample size of white dwarf debris disks combined with timely advancement in disk modeling efforts have made this new exploration feasible.