In a medium bowl, whisk the eggs with 1/4 cup of the milk and the salt until blended. Whisk in the flour until the batter is smooth, then whisk in the remaining 1 cup of milk and 1 tablespoon of the melted butter. Let the crêpe batter stand at room temperature for about 20 minutes.
In a small saucepan, combine the apricot preserves with the raspberries and lemon juice and cook over moderate heat until jammy, about 5 minutes. Cover and keep warm.
In a bowl, mix the yogurt with the brown sugar and vanilla.
Heat a 10-inch crêpe pan or nonstick skillet over moderate heat. Brush the pan with some of the melted butter. Pour in a scant 1/3 cup of the crêpe batter and immediately rotate the pan to evenly coat the bottom. Cook the crêpe until lightly browned on the bottom, about 45 seconds. Flip the crêpe and cook until brown dots appear on the other side, about 15 seconds longer. Transfer the crêpe to a large baking plate covered with parchment paper. Continue making crêpes with the remaining batter, brushing the pan with the remaining melted butter as needed.
Spoon 3 tablespoons of the yogurt onto each crêpe and roll them up. Transfer to plates. Spoon the raspberry-apricot sauce on top and serve.
The crêpes can be made ahead and stacked, then rewarmed in a microwave oven for about 20 seconds.