In a large saucepan, combine potatoes and garlic. Add enough lightly salted water to cover by 1 inch. Bring to a boil. Reduce heat; simmer, covered, for 20 minutes, or until potatoes are tender. Remove from heat; drain well.
Return potatoes and garlic to saucepan and place back on the heat for 1-2 minutes to evaporate any excess moisture. Remove from heat.
Mash potatoes and garlic until smooth. Gradually blend in broth, oil, salt, and pepper. Whip until light and creamy. Stir in scallions.
Line a rimmed baking with parchment paper.
Using an ice-cream scoop, scoop rounded mounds of potato mixture onto prepared baking sheet. (Can be made in advance up to this point.)
Preheat oven to 375°F.
Bake, uncovered, for 25-30 minutes, until crusty.