1. 1. Preheat the oven to 375°F (190°C).

2. 2. In a large mixing bowl, combine the heavy cream, mayonnaise, and softened butter. Mix until smooth.

3. 3. In a separate bowl, whisk together the flour, salt, sugar, and baking powder. Gradually add the dry ingredients to the cream mixture, mixing until a dough forms.

4. 4. Divide the dough into 8 equal pieces and roll each into a ball. Flatten each ball into a thin circle.

5. 5. Place a salmon fillet (or crayfish) in the center of each dough circle. Spoon some of the shrimp cream on top of the fish.

6. 6. Fold the dough over the filling to form a triangle or square shape and press the edges together to seal.

7. 7. Place the pastries on a baking sheet lined with parchment paper, leaving about 1 inch of space between each pastry.

8. 8. Brush the tops with cold water and sprinkle with chopped fresh dill.

9. 9. Bake for 20 to 25 minutes or until the pastry is golden brown.

10. 10. Handle hot pastries with care to avoid burns.