PA-44 Flight Instructor reported engine failure in cruise flight. They returned to the departure airport and landed uneventfully.

Narrative

Pre-flight inspection and briefing completed in accordance with 14 CFR 91.103. Six quarts of oil observed in both engines. Fuel quantity verified at fifty gallons per wing (one hundred total). No discrepancies noted during pre-flight; engine start; taxi; or run-up.Departed ZZZ runway XX from intersection 1 on a VFR south departure. Takeoff was normal with all indications in the green. Climbed to the south practice area and maneuvered at approximately 4;500 feet MSL. During throttle adjustments; the right engine manifold pressure gauge exhibited intermittent sticking on three occasions; but remained responsive. Condition assessed as a possible instrumentation anomaly.During a steep turn maneuver; the right engine (engine two) developed significant roughness. Engine failure procedures initiated. Troubleshooting checklist accomplished with no corrective effect. Indications observed: right oil pressure decreasing toward the yellow/red range; cylinder head temperature above normal; fuel pressure normal; white smoke visible from right engine.Decision made to secure engine two. Propeller feathered; mixture cutoff; and engine secure checklist completed. Requested priority handling with Approach and reported single-engine operations inbound to ZZZ.Intercepted the localizer for runway XY and conducted a stabilized single-engine approach; maintaining airspeed. Normal landing accomplished on runway XY. Aircraft exited at taxiway 2 and shut down. Aircraft was hand-towed to ramp and secured.No injuries; no collateral damage; no additional assistance required.