Sift the flour into a bowl, add the diced butter, salt and beaten egg. Mix the ingredients until you get a homogeneous dough that you wrap in a food foil and put it in the fridge for an hour.
Peel a squash, grate it and squeeze the juice.
In a saucepan, bring salted water to a boil. When the water boils, add the cleaned asparagus and boil it for 3-5 minutes, until it softens a little, but remains crispy. Using a spatula, remove the asparagus in a bowl with cold water and ice (to keep the color of the asparagus as green as possible). After 2 minutes, take it out and let it drain well.
You use a part of the asparagus to fill the preparation and a part for the asparagus puree (about a quarter of the amount of asparagus).
(To make it easier to navigate, you can arrange the asparagus sticks on top of the salmon fillet, so you'll see exactly what you need.)
What's left, use for asparagus puree. Finely chop the asparagus that you stopped for the puree and pass it through the blender. Add sour cream, chopped dill, lemon peel, salt and pepper to taste. Homogenize the composition very well.
Divide the dough into 2 parts and spread the first sheet.
In a tray lined with baking paper, place a sheet of dough and grease it with beaten egg. Over the sheet, place the salmon fillet well dampened with water, sprinkle with salt and pepper. Grease the entire surface of the salmon fillet with the asparagus puree, and place the asparagus stalks on top of it. Cover the fillet with the other sheet of dough, seal the edges well and press them with a fork. Grease the dough with beaten egg and prick with a fork in several places to allow the steam to come out.
Put the tray in the preheated oven at 180 degrees C and bake until browned, about 35-40 minutes.
When ready, take the tray out of the oven and let it cool a bit before serving.
For the garnish, I used 5 asparagus stalks, which I scalded for 2 minutes, I took them out in ice water, then I let them drain. I tamponed the excess water well, then I put them on the hot grill for 2-3 minutes on both sides.