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

Heat 2 tablespoons of olive oil in a medium skillet over medium heat. Sauté one finely chopped small onion until translucent, about 3-4 minutes. Add 2 minced garlic cloves and cook for an additional minute.

Add 4 cups of fresh baby spinach to the skillet and stir until wilted, about 2-3 minutes. Remove from heat and let cool.

In a mixing bowl, combine the cooled spinach mixture with 8 ounces of softened cream cheese and 2 tablespoons of fresh chopped dill. Season with salt and pepper and mix until combined.

Pat 2 salmon fillets dry with paper towels and season both sides with salt and pepper.

Roll out thawed puff pastry on a floured surface, cutting it into four 6-inch squares.

Place a quarter of the spinach mixture in the center of each pastry square and top with a salmon fillet. Fold pastry over to encase the filling and pinch edges to seal.

Score shallow cuts in a crisscross pattern on top of each Wellington. Brush with beaten egg.

Transfer to the baking sheet and bake for 20-25 minutes, until golden brown and the internal temperature of the salmon reaches 145°F (63°C).

Let rest for 5 minutes before serving with lemon wedges.