How to Make It
In a medium bowl, whisk the buckwheat flour with the eggs and half of the milk until lump-free. Add the remaining milk and whisk until smooth. Refrigerate the batter for 20 minutes.
Line a plate with wax paper. Heat an 8-inch nonstick skillet and lightly brush with olive oil. Add 1/4 cup of the batter to the skillet and swirl to coat the pan. Cook over moderate heat until the edges begin to pull away from the pan, 30 seconds to 1 minute. Flip the crêpe and cook 30 seconds to 1 minute longer. Transfer the crêpe to the prepared plate and repeat with the remaining batter.
Slather each crêpe with 1/2 tablespoon of Dijon. Divide the turkey slices between the crêpes and top with half a sliced avocado. Drizzle with the lemon juice, season with salt and serve.