Combine spinach, cream cheese,Worcestershire sauce, salt, onion powder, garlic powder, black pepper, and parmesan cheese in a bowl. Mix until fully combined.
Season salmon with a little bit of salt and pepper. Lay puff pastry on flat surface and roll until smooth. In the center of the pastry, add half of the spinach mixture, then lay salmon on top, then add remaining spinach mixture on top.
Fold over sides of puff pastry to enclose spinach and salmon inside the pastry. Flip the pastry over and place on sheet pan lined with parchment paper. Score the pastry with a pairing knife and brush egg over the pastry.
Bake in preheated oven for 30-35 minutes or until the top is nice and golden. Remove and enjoy.
Thaw the puff pastry sheet according to the instructions on the package.
You can cut the spinach and cheese mixture in half if you prefer and place the mixture on one side of the salmon.