- 2 3/4 pounds russet potatoes, peeled cut into 2-inch pieces
- 1/2 cup coarsely chopped shallots
- 1 3/4 cups (packed) grated extra-sharp cheddar cheese (about 8 ounces)
- 1 cup half and half
- 1/4 teaspoon cayenne pepper
- 2 large green onions, thinly sliced
- Cook potatoes and shallots in large pot of boiling salted water until potatoes are tender, about 25 minutes. Drain, reserving 1 cup cooking liquid. Return potato mixture to same pot.
- Meanwhile, stir 1 1/2 cups cheese and half and half in heavy small saucepan over medium heat until smooth. Add cheese mixture and cayenne to potatoes. Mash until smooth and fluffy, adding enough reserved cooking liquid to thin to desired consistency. Season with salt. (Can be made 2 hours ahead. Cover; let stand at room temperature. Rewarm over low heat, stirring.) Transfer to bowl. Top with green onions and 1/4 cup cheese.