In a large skillet, melt 1 tablespoon of butter over medium heat. Add 2 cups of fresh spinach and 2 cloves of minced garlic, sautéing for around 2-3 minutes until the spinach wilts and releases its moisture. Remove from heat and mix in 1 cup of your chosen cheese.

On a lightly floured surface, roll out one sheet of thawed puff pastry to about ⅛ inch thick.

Place a salmon fillet in the center of the rolled-out puff pastry. Spoon the spinach and cheese mixture over the salmon.

Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper and set the assembled Spinach Cheese Stuffed Salmon Wellington on it, seam side down. Bake for about 30 minutes, or until the pastry is golden brown.

Once out of the oven, let the Spinach Cheese Stuffed Salmon Wellington cool for about 5 minutes before serving.