Make egg salad:Stir together all ingredients and a pinch of salt.
Make blini: Whisk together dry ingredients in a bowl. Add milk and yolk and whisk until smooth. 3Beat egg white with a clean whisk in another bowl until it just holds soft peaks. Fold into batter along with 2 tablespoons melted butter.
Brush a 12-inch nonstick skillet with some of remaining melted butter, then heat over medium heat until hot. Working in batches of 6 or 7, drop 1 level tablespoon batter per pancake into skillet and cook until bubbles appear on surface and undersides are golden, 45 seconds to 1 minute. Flip over and cook 1 minute more. Brush blini on both sides with some of remaining melted butter, then transfer to a plate and keep warm, covered with foil. Brush skillet with butter between batches.
Fill tortes: Drape smoked salmon on 6 blini and top with egg salad. Spoon caviar onto 6 more blini, then stack on egg-salad-topped blini.
For egg salad
- 1 hard-boiled large egg, finely chopped
- 2 tablespoons sour cream
- 1 tablespoon finely chopped chives
- For blini
- 2 tablespoons buckwheat flour
- 3 tablespoons all-purpose flour
- 1 teaspoon sugar
- 1/8 teaspoon baking soda
- 1/8 teaspoon salt
- 1/4 cup whole milk
- 1 large egg, separated
- 1/2 stick unsalted butter, melted and cooled, divided
- 1/4 lb thinly sliced smoked salmon at room temperature
- 2 ounces trout caviar, such as rainbow- trout caviar, or salmon roe
- Garnish: sour cream; chopped chives