Pat each cod fillet completely dry with paper towels. Dry fish sears faster and prevents steaming. Sprinkle both sides with the salt, pepper, and lemon zest, then lightly rub with softened butter.

Place a large non-stick or stainless-steel skillet over medium-high heat for 2 minutes so the surface is evenly hot. Add the tablespoon of olive oil and swirl to coat.

Lay the seasoned fillets in the hot pan presentation side down. Cook 3 to 4 minutes until the edges turn opaque and a golden crust forms. Flip gently with a thin spatula and cook another 2 to 3 minutes. Transfer the fish to a plate and tent loosely with foil to keep warm.

Reduce heat to medium. Add minced garlic to the same skillet and stir 30 seconds until fragrant, watching closely to avoid burning. Pour in lemon juice and broth. Scrape up any browned bits with a wooden spoon; these add deep flavor. Simmer 1 minute until slightly reduced.

Stir in chopped parsley, basil or dill, and a pinch of red-pepper flakes if using. Taste and adjust seasoning, adding a small splash of broth if the sauce seems too thick.

Push the sauce to one side of the pan. Add the extra teaspoon of olive oil and the spiralized zucchini. Sprinkle with the remaining salt and toss continuously for 1 to 2 minutes until just tender and bright green. Do not overcook; the noodles should stay crisp to avoid excess water.

Return the cod fillets to the skillet, nestling them on top of the zoodles. Spoon some sauce over each piece. Warm everything together for 1 minute so flavors meld.

Divide zucchini noodles among plates, top with cod, and drizzle with the remaining lemon herb sauce. Garnish with extra herbs and lemon wedges for a fresh finish.