Scallion Potato Pancake and Smoked-Salmon Sandwiches

Ingredients

• 2 tablespoons capers rinsed
• 0.5 cup crème fraîche sour
• 0.5 small onion red thinly sliced
• 2 pounds baking potatoes (baking) ( 4 large)
• 0.5 cup spring onion finely chopped
• 0.8 pound salmon smoked sliced
• 2.5 tablespoons butter unsalted
• 5 tablespoons vegetable oil 

Equipment

• food processor
• frying pan
• baking sheet
• paper towels
• oven
• spatula

Directions

1. Preheat oven to 450°F.
2. Peel potatoes and coarsely grate in a food processor. Stir together potatoes and scallions.
3. 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.
4. 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.
5. Reheat cakes in oven 3 to 5 minutes, or until crisp. Make sandwiches with pancakes, salmon, onion, capers, and crème fraîche.