Preheat the oven to 375°F (190°C).
Heat the olive oil in a skillet over medium heat.
Add the minced garlic and cook for about 30 seconds until fragrant.
Stir in the fresh spinach and cook until wilted.
Season with salt, pepper, and dried thyme.
Arrange the salmon fillets on a parchment-lined baking sheet.
Spoon the spinach mixture evenly over each fillet.
Drizzle fresh lemon juice over the salmon.
Sprinkle each fillet with grated Parmesan cheese.
Place a small pat of butter on top of each fillet.
Bake the Baked Salmon with Spinach for 15–20 minutes, or until the salmon flakes easily with a fork.
Serve immediately with your favorite vegetables, rice, or roasted potatoes.