How to Make It
Whisk together eggs, flour, baking powder, pepper, and 1 teaspoon of the salt in a medium bowl.
Grate potato and onion, using the grating attachment of a food processor; spread mixture on a clean towel, and roll up. Wring towel to squeeze out as much liquid as possible. Stir potato mixture into egg mixture. Grate turnip, and fold into potato mixture.
Heat oil in a large nonstick skillet over medium-high. Drop batter by 2 tablespoonfuls into hot oil, keeping 3 inches between latkes. Using a spatula, flatten each latke to ⅓-inch thickness, and cook until golden brown, 2 to 3 minutes per side. Sprinkle with a pinch of remaining ¼ teaspoon salt after turning. Drain on paper towels, and repeat with remaining batter and salt.
Top each latke with a slice of smoked salmon and a dollop of crème fraîche. Garnish with dill, if desired.