Recent measurements of jet structure modifications at RHIC and LHC highlight the importance of differential measurements to study the nature of jet quenching. Since these jet observables are intimately dependent on parton shower in both the angular and energy scales, differential measurements are required to disentangle these two scales in order to study the medium's characteristic properties such as the coherence length. I will talk about recent jet substructure measurements from the STAR collaboration in both p+p and Au+Au collisions and what we learn from such differential measurements.