Pat fillets dry with paper towels — this is key to avoiding mushy results. Lay them in a single layer on a foil-lined or greased baking sheet with space between each fillet. Season with salt, pepper, and your preferred seasoning (lemon-pepper, Italian herbs, or paprika all work). Optional: brush with olive oil or egg wash and press into breadcrumbs or Parmesan for a crispy crust. Add any vegetable or spinach toppings directly onto the fillets before baking.

Preheat oven to 400°F. Place fillets on the middle rack and bake 10–12 min for thin fillets (3–4 oz) or 15–16 min for thicker fillets or those with toppings. Do not flip. Fish is done when opaque and flakes easily with a fork. Internal temp should reach 140°F. Check at 10 min if fillets are thin or your oven runs hot.

Pull the baking sheet at 140°F internal temp or when fish flakes easily—residual heat keeps cooking, so don't overbake. Rest fillets on the sheet 1–2 minutes, then plate immediately. Serve with lemon, fresh herbs, or sides. Leftovers: reheat covered at 350°F until warmed through.