Rinse the fresh spinach and shake off excess water. Roughly chop if the leaves are large.

Season fillets lightly with salt and pepper.

Heat olive oil in a large skillet over medium-high heat. Add fillets skin-side down if using skin-on; press gently for 10–15 seconds.

Cook for 3–4 minutes without moving, until edges turn opaque and golden. Flip and cook another 2–3 minutes until fish is just cooked (internal temp ~130–140°F). Transfer to a warm plate.

Lower heat to medium. Add butter to the same skillet and let it melt, scraping up any browned bits.

Add minced garlic and cook 30–45 seconds until fragrant.

Pour in white wine (or broth) and simmer 1–2 minutes until slightly reduced.

Stir in lemon juice and zest, capers (if using), and chopped parsley. Taste and adjust salt or lemon.

Return fillets to the skillet for 30 seconds in the sauce to reheat and coat lightly.

Transfer to plates.

In a second large skillet, melt butter over medium heat. Sauté the shallot until soft (about 2 minutes).

Add garlic and cook for 30 seconds.

Add spinach in batches, stirring until wilted.

When all spinach is wilted, fold in cream cheese (or heavy cream) and Parmesan, stirring until smooth and glossy.

Add a pinch of nutmeg, salt, and pepper to taste. If the mix is too thick, splash in a tablespoon of milk or water to loosen.

Spoon a generous bed of creamed spinach onto each plate and set the fillet on top.

Drizzle additional lemon-garlic sauce over the fish and serve with lemon wedges and a sprinkle of parsley.