Serves 4 as a main dish, can be doubled
4 (6-ounce) center cut salmon fillets, skin removed (equal size pieces)
1 lemon, zested and juiced
Kosher salt and freshly ground black pepper
4 tablespoons canola oil, divided
1 medium Vidalia onion, chopped
2 cloves garlic, minced
1 cup chopped shiitake mushrooms, stems discarded
2 teaspoons chopped fresh thyme leaves
4 cups washed, dried, and loosely packed fresh baby spinach
1/4 cup sour cream
2 frozen puff pastry sheets, defrosted
Chopped fresh parsley leaves, for garnish
Preheat the oven to 375 degrees.
Brush both sides of the salmon with 1 teaspoon lemon juice and sprinkle with salt and pepper, to taste. Set aside.
Warm 2 tablespoons oil in 2 separate skillets over medium-high heat. Add half of the onion and half the garlic to each pan. Season with salt and pepper, to taste, and sauté until tender, about 5 minutes. Stir in the mushrooms and thyme into 1 pan and the spinach, lemon zest and remain lemon juice in the other pan. Stir the spinach until it wilts, then transfer it to a bowl and set aside. Sauté the mushrooms until they are reduced and tender, about 5 minutes. Turn off the heat and stir in the sour cream. Set aside.
Unroll a pastry sheet on a lightly floured surface. With a rolling pin lightly seal the seams and lengthen the dough slightly. Cut the pastry sheet into 3 equal strips, using the natural seams as a guide. Roll out the second puff pastry sheet to get 1 more strip. Save remaining puff pastry for another use. Lightly prick the 4 strips with a fork. Put 1 heaping spoonful of mushroom mixture on 1 half of each pastry, top with salmon, and then layer with a heaping spoonful of spinach mixture. Wet the edges of the pastry with water and fold over the other half, pressing lightly and folding to seal the edges. Repeat with remaining pastry and filling. Cut 2 vents on the top of each pastry packet and arrange them on a parchment-lined baking sheet.
Bake until the pastry is golden and fish is just opaque in the center, about 25 to 30 minutes.
Garnish with chives or parsley and serve with honey mustard sauce if you wish.