We present a novel integration of a brain-computer interface (BCI) with a music step sequencer composition program. Previous BCIs that utilize EEG data to form music provide users little control over the final composition or do not provide enough feedback. Our interface allows a user to create and modify a melody in real time and provides continuous aural and visual feedback to the user, thus affording them a controllable means to achieve creative expression. Keywords Brain-Computer Interface, P300 Evoked Potential, Music composition ACM Classification Keywords H5.5. Information interfaces and presentation (e.g., HCI): Sound and Music Computing General Terms Design, Experimentation