To make cured salmon you will need to start the day before you’re planning to serve it. In a small bowl, combine salt and sugar. Spread half of the salt mixture in a small container, which can hold the filet.
Place the salmon skin-side down and cover with the rest of salt and sugar. Close the container with a lid, or cover with a plastic wrap. Refrigerate for 12 to 16 hours, but no longer or the fish might get too salty and dry.
Scrape off salt and rinse with cold water. Then pat dry with a paper towel and place in a storage container. Enjoy within 1 week.
In a medium bowl, combine the flours, sugar, and salt. In a large bowl, whisk the eggs, waater and milk until well mixed. Beat in the flour mixture until smooth. An old-school whisk will do the job just fine. But if you have an immersive blender, it will make the batter even smoother. Then stir in 3 tablespoons of the melted butter. Cover with a plastic wrap and leave rest at room temperature for 30 minutes.
Gently stir the batter if it separates. Heat a non-stick or crepe pan over medium-high heat until really hot. Cover the pan with a thin layer of oil, and pour a small amount of batter. Rotate the pan to spread batter as thinly as possible. Cook over moderate heat until lightly browned on the edges, about 1 minute. Loosen the edges with a spatula and flip over the crepe. Cook on the other side for about 20 seconds. Transfer the crepe to a platter. Repeat with the remaining batter. Serve hot, In a small bowl mix sour cream and chopped fresh herbs and serve with hot crepes and thinly sliced cured salmon.