We propose a Delayed-Choice Quantum Eraser (DCQE) operating under Mach-Zehnder setup augmented with the off resonant cavity QED atom-field interactions. The proposed DCQE completely highlights all the counterintuitive ideas of the quantum theory while shedding ample light over the themes of coherence, conception of the time in quantum theory, measurement, information and the entropy. The setup is certainly helpful to clarify some features of the ongoing dialogue about the ontological (epistemological) nature of the state vector. Furthermore, this proposal for the fully deterministic experiment can be easily executed under the prevailing research scenario with good fidelity.