Preheat oven to 450 degrees. Prepare potatoes as package directs.
Remove stems from mushrooms; chop stems and set aside. Carefully scoop out center of each mushroom cap with a spoon, leaving 1/2-inch shell.
Melt butter in 10-inch skillet over medium heat. Add chopped mushroom stems and cook for 3 minutes or until tender. Remove from heat and stir in mashed potatoes, 2 tablespoons chives and salt.
Fill each mushroom cap with potato mixture, mounding it slightly. Bake for 10 minutes or until potatoes are lightly golden. Sprinkle mushrooms with remaining 1 tablespoon chives.
All materials courtesy of Idahoan Foods and Swanson Broth. For more easy-entertaining recipes, visit www.swanson stock.com and www.idahoan.com