Skip the sour cream and give a mushroom-topped spud a better finish: a generous dollop of yogurt, plus a little cheddar and chives.
Preheat oven to 450 degrees. Bake potatoes on a rimmed baking sheet until skins are crisp and flesh is tender, 45 to 50 minutes.
Heat oil in a medium skillet over medium-high heat. Add mushrooms; cook, stirring, until browned, about 2 minutes. Stir in salt; season with pepper.
Slit the potatoes lengthwise, stopping 1/2 inch from ends. Gently squeeze ends to loosen flesh. Open each potato slightly. Divide sauteed mushrooms and the cheese among potatoes; top each with 1 tablespoon yogurt. Garnish with chives.