Salmon Wellington with Quark Pastry

MAKE THE QUARK PASTRY:
1. Combine flour, baking powder, and salt in a large bowl. Whisk to distribute evenly.
2. Add cold butter cubes. Using a pastry cutter or your fingertips, work butter into flour until mixture resembles coarse breadcrumbs with some pea-sized pieces remaining. Work quickly to keep butter cold.
3. Add cold quark. Mix with a fork or your hands until dough just comes together—it will be soft and slightly sticky. Do not overwork.
4. Turn dough onto a lightly floured surface and shape into a rectangle. Wrap tightly in plastic wrap and refrigerate at least 30 minutes (up to overnight).

PREPARE THE RICE:
5. Rinse rice under cold water until water runs clear.
6. Combine rice, water, and salt in a small saucepan. Bring to a boil, reduce heat to low, cover, and simmer 15-18 minutes until water is absorbed and rice is tender.
7. Fluff with a fork, stir in butter, dill, chives, and lemon zest. Season to taste. Spread on a plate to cool completely.

PREPARE THE MUSHROOM-SPINACH LAYER:
8. Melt butter in a large skillet over medium-high heat. Add shallot and cook until softened, 2 minutes.
9. Add mushrooms and cook, stirring occasionally, until they release their liquid and it evaporates, 8-10 minutes. The mushrooms should be quite dry.
10. Add garlic, cook 30 seconds until fragrant.
11. Add wine and cook until evaporated.
12. Add spinach in handfuls, stirring until wilted. Cook until any liquid evaporates completely.
13. Season with nutmeg, salt, and pepper. Transfer to a plate and cool completely. Press with paper towels to remove any remaining moisture.

PREPARE THE EGG LAYER:
14. Peel hard-boiled eggs and chop finely.
15. Mix with mayonnaise, mustard, and dill. Season with salt and pepper. Set aside.

PREPARE THE SALMON:
16. Season salmon fillet on both sides with salt and pepper. Drizzle with olive oil and lemon juice.
17. If salmon fillet is very thick, you may briefly sear it in a hot pan for 1 minute per side to develop color. Otherwise, use raw; it will cook through during baking.

ASSEMBLE THE WELLINGTON:
18. Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
19. On a lightly floured surface, roll quark pastry into a rectangle approximately 14x12 inches, large enough to fully encase the salmon with a 2-inch border on all sides.
20. Transfer pastry to prepared baking sheet.
21. Build the layers in the center of the pastry, leaving borders clear: First, spread the cooled rice in an even layer the size of the salmon fillet. Next, spread the mushroom-spinach mixture over the rice. Then, spread the egg mixture over the mushrooms. Finally, place the salmon fillet on top.
22. Brush pastry borders with egg wash.
23. Fold the short ends of the pastry over the salmon first, then fold the long sides up and over, pressing to seal. Pinch seams firmly.
24. Carefully flip the Wellington seam-side down. Tuck ends under neatly.
25. Brush entire surface generously with egg wash. Score decorative lines or patterns with a sharp knife if desired—be careful not to cut through.
26. Sprinkle with flaky sea salt and seeds if using.
27. Cut 2-3 small steam vents in the top.

BAKE:
28. Bake 35-40 minutes until pastry is deep golden brown and crisp. A thermometer inserted through a steam vent into the salmon should read 125-130°F (52-54°C) for medium, 140°F (60°C) for well done.
29. Rest 10 minutes before slicing—this allows the salmon to finish cooking gently and the juices to redistribute.

TO SERVE:
30. Using a sharp serrated knife, cut into thick slices, revealing the colorful layers.
31. Serve with lemon wedges, crème fraîche, or a simple dill-cucumber salad.