Step 1: Prepare the Filling

1. Heat the olive oil in a skillet over medium heat. Add the minced garlic and chopped shallot, sautéing for 1-2 minutes until fragrant.
2. Stir in the chopped spinach, cooking until wilted, about 3-4 minutes. Season with salt and pepper.
3. Remove the skillet from heat and allow the spinach mixture to cool for 5 minutes.
4. In a mixing bowl, combine the spinach mixture, softened cream cheese, Parmesan cheese, and fresh dill (if using). Mix until well combined. Set aside.

Step 2: Prepare the Salmon

1. Pat the salmon fillets dry with a paper towel. Season both sides with salt, pepper, and smoked paprika (if desired).
2. Spread a thin layer of Dijon mustard over one side of each salmon fillet to enhance the flavor.

Step 3: Roll Out the Puff Pastry

1. Lightly flour a clean surface and roll out the puff pastry into a rectangle large enough to wrap both salmon fillets.
2. Cut the pastry into two equal pieces, ensuring each piece is large enough to fully enclose a salmon fillet and filling.

Step 4: Assemble the Wellington

1. Place one piece of puff pastry on the prepared baking sheet. Spread a layer of the spinach filling in the center, leaving a 1-inch border around the edges.
2. Lay a salmon fillet on top of the filling, Dijon mustard side down.
3. Fold the pastry over the salmon, sealing the edges by pinching or crimping with a fork. Repeat for the second fillet.
4. Brush the top and edges of each Wellington with the beaten egg to ensure a golden crust during baking.

Step 5: Bake the Wellingtons

1. Preheat your oven to 400°F (200°C).
2. Place the baking sheet in the oven and bake for 30-35 minutes, or until the puff pastry is golden brown and crispy.
3. Remove the Wellingtons from the oven and allow them to rest for 5 minutes before serving.