That's a clever shortcut! Using the microwave does indeed make the process quicker. As far as I know, microwaved sweet potatoes are softer and moister. I personally love the golden-brown color of roasted potato cubes.🙃
Scrubbing sweet potatoes, as a pre-peeling step, helps remove any lingering dirt or residue on the skin that might transfer to the peeled surface during preparation. Also, it helps to keep the razor sharp longer.
