Salmon en Croute with Lemon-Dill Sauce

Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.

In a large skillet, heat olive oil over medium heat. Add shallots and mushrooms and cook until softened, about 5 minutes.

Pour in white wine and simmer until reduced by half, about 5 minutes.

Stir in heavy cream, dill, and lemon juice. Season with salt and pepper to taste. Remove from heat and stir in butter.

Pat the salmon fillet dry with paper towels and season with salt and pepper.

On a lightly floured surface, unfold the puff pastry sheet. Cut in half.

Place one half of the puff pastry on the prepared baking sheet. Spread the mushroom mixture evenly over the pastry, leaving a 1-inch border.

Place the salmon fillet on top of the mushroom mixture.

Top with the other half of the puff pastry. Press the edges together to seal. Crimp the edges with a fork to create a decorative border.

Brush the top of the pastry with the beaten egg.

Cut a few slits in the top of the pastry to allow steam to escape.

Bake for 30-35 minutes, or until the pastry is golden brown and the salmon is cooked through.

While the salmon is baking, prepare the Lemon-Dill Sauce: In a small bowl, whisk together mayonnaise, dill, lemon juice, Dijon mustard, salt, and pepper.

Let the salmon en croute cool slightly before slicing and serving. Serve with the Lemon-Dill Sauce.