Pierce the potato all over with a paring knife and microwave on high power until tender, about 7 minutes. Set aside.
Put the half-and-half in a medium bowl and loosely cover with plastic wrap. Microwave on high until just simmering, about 45 seconds.
Halve the potato lengthwise and hold each half in a towel or oven mitt (it will be hot). Scoop out the insides of each half with a fork into the warm half-and-half. Add the butter and use the fork to mash the potatoes. Season with salt and pepper. Eat and be comforted.