Follow these simple steps to create your Salmon En Croute:

1. Preheat Oven: Preheat your oven to 400°F (200°C).
2. Prepare Filling: In a bowl, combine the chopped spinach, cream cheese, dill, and shallots. Mix well and season with salt and pepper.
3. Prepare Salmon: Place the salmon fillet on a clean surface. Season it with salt and pepper, then spread the cream cheese mixture evenly over the top.
4. Roll Out Pastry: On a floured surface, roll out the puff pastry until it’s large enough to wrap around the salmon.
5. Wrap Salmon: Carefully place the salmon in the center of the pastry. Fold the pastry over the salmon, sealing the edges to prevent any filling from leaking out.
6. Brush with Egg: Place the wrapped salmon on a baking sheet lined with parchment paper. Brush the surface with the beaten egg for a golden finish.
7. Make Slits: Using a sharp knife, make a few slits on top of the pastry to allow steam to escape during baking.
8. Bake: Place in the preheated oven and bake for 30-35 minutes, or until the pastry is golden brown and flaky.
9. Rest: Remove from the oven and let it rest for 10-15 minutes before slicing.
10. Slice and Serve: Cut the Salmon En Croute into portions and serve warm with lemon wedges.

These steps will guide you in creating an incredible dish that will impress everyone at your table.