Scrub and pierce potatoes; place on a microwave-safe plate. Microwave, uncovered, on high for 10-12 minutes or until tender, turning once.
When cool enough to handle, cut potatoes in half lengthwise. Scoop out pulp, leaving a thin shell. In a large bowl, mash the pulp with butter. Stir in the sour cream, garlic, salt and pepper. Spoon into potato shells.
Place on a microwave-safe plate. Sprinkle with cheese. Microwave, uncovered, on high for 1-2 minutes or until heated through.