Line a rimmed baking sheet with parchment paper; set aside.
Season the salmon with salt and pepper to taste.
In a large skillet over medium heat melt the butter. Sauté shallots and garlic until the shallots become translucent.
Turn the heat to medium-high and add the white wine. Let the liquid cook off about 3-4 minutes, then add the cream cheese; sauté for 1 minute.
Add the spinach, bread crumbs, and Parmesan cheese. Sauté just until the spinach wilts.
Unfold the puff pastry onto a lightly floured surface and roll out the 2 sheets, then cut them in half. So you end up with 4 pieces. Make each piece about 10 x 14-inches.
Place each seasoned salmon fillet in the middle of each puff pastry sheet. Depending on the size of the fillet, you may need to roll out the puff pastry a little more or less. Leave about 2 inches around the edges.
Divide the spinach mixture into 4 equal parts and evenly spread it on top of the 4 fillets. Then brush the edges of the puff pastry with egg wash (1 egg + 1 tsp water).
Begin folding the puff pastry over starting with the longer side. When folding over the short edges, brush more of the egg wash before folding.
Place the salmon wellington seam side down on the prepared baking sheet.With a sharp knife make crosshatch slits on top of the Wellington, then brush with egg wash.
Bake at 400 degrees for 20-25 minutes or until the pastry is golden brown.