How to Make It
In a small bowl, stir the crème fraîche with the dill and lemon juice. Season with salt and black pepper and sprinkle with the chives. Refrigerate until ready to serve.
In a food processor or on a box grater, coarsely shred the potatoes and the onion. Transfer to a large, clean kitchen towel and squeeze dry.
In a medium bowl, mix the shredded potatoes and onion with the egg, flour, baking powder, 1 teaspoon of salt and 1/4 teaspoon of black pepper.
In a large nonstick skillet or on a griddle, heat the vegetable oil until shimmering. Drop 2 tablespoons of the potato mixture into the skillet and flatten with the back of a spoon to make a 3-inch round. Make about 5 more pancakes and cook over moderately high heat until golden on the bottom, about 4 minutes. Flip the pancakes and cook until golden, about 2 minutes longer. Transfer to paper towels to drain. Repeat with the remaining potato mixture; you should have 12 pancakes.
Arrange the potato pancakes on a platter. Serve warm, with the dill cream, smoked salmon and caviar.