- 2 pounds russet (baking) potatoes (about 4 large)
- 1/2 cup finely chopped scallion greens
- 5 tablespoons vegetable oil
- 2 1/2 tablespoons unsalted butter
- 3/4 pound sliced smoked salmon
- 1/2 small red onion, thinly sliced
- 2 tablespoons capers, rinsed
- 1/2 cup crème fraîche or sour cream
- Preheat oven to 450°F.
- Peel potatoes and coarsely grate in a food processor. Stir together potatoes and scallions.
- Heat 1 tablespoon oil with 1/2 tablespoon butter in a 12-inch nonstick skillet over moderately high heat until foam subsides. Scoop 3 (1/4-cup) mounds of potato mixture into skillet, flattening with a spatula to form 3 1/2- to 4-inch pancakes. Reduce heat to moderate and cook, pressing down occasionally on cakes with a metal spatula (to compact cakes and prevent them from breaking when turning), until golden brown and crisp on undersides, 6 to 8 minutes. Turn cakes over carefully and cook, pressing occasionally, until golden brown and crisp, about 8 minutes more. Drain on paper towels, then arrange on a large baking sheet. Make more pancakes in same manner with remaining oil and butter, wiping skillet clean with paper towels between batches.
- Reheat cakes in oven 3 to 5 minutes, or until crisp. Make sandwiches with pancakes, salmon, onion, capers, and crème fraîche.