Lemon Herb Fish Baked in Foil with Potatoes

This Baked Fish in Foil with Potatoes is a simple, gluten-free weeknight dinner that delivers big flavor with very little fuss. Flaky cod fillets rest on a bed of thinly sliced, buttery potatoes, brightened with lemon and fragrant fresh thyme. Everything is baked in individual foil packets for a tidy, steam-infused finish and minimal cleanup.

Cooking fish in foil is a reliable way to steam the fillets gently while roasting vegetables at the same time. The foil traps moisture and flavor so the fish stays tender and the potatoes cook through without drying out. This method is great for portion control and makes serving effortless — just open each packet at the table for a little theatrical flourish.

Ingredients for oven baked fish and potatoes

• Fresh cod fillet – or another firm white fish with similar texture, such as halibut, haddock or bass. Avoid very dense steaks like swordfish unless you adjust cooking time.
• Yellow potatoes, thinly sliced – thin slices cook quickly and form a nice base for the fish. You can also use pre-sliced seasoned potatoes if pressed for time.
• Butter – unsalted butter is ideal; substitute vegan butter for a dairy-free version.
• Lemon – sliced for baking and a squeeze of fresh juice when serving.
• Sea salt and black pepper – to taste. Optional: a pinch of bay seasoning or your preferred seafood seasoning.
• Fresh thyme – or use parsley, dill or cilantro as a garnish, especially in warmer months.

This foil-packet cod with lemon and butter uses just a few ingredients and relies on technique: bake the potato slices first to ensure they’re tender with a slightly crisp edge, then add the fish and finish until the fillets are flaky and cooked through.

Make ahead and storage

You can assemble the foil packets up to 24 hours ahead and keep them covered in the refrigerator until you’re ready to bake. Leftovers store well in an airtight container for up to 48 hours. Reheat gently in a 300–325°F oven or air fryer until warmed through to avoid drying the fish.

This gluten-free fish dinner is a year-round favorite and a clean source of protein. In warm weather, the foil packets can be cooked on a grill for a lightly charred flavor; in cooler months, the oven produces reliably tender results. Serve with a crisp green salad, steamed greens, or roasted vegetables for a balanced plate.

Fish lover? Delicious variations and serving ideas

If you enjoy this dish, try small variations to keep it fresh: swap thyme for dill and use a lemon-dill butter for a Scandinavian twist, or sprinkle panko and grated Parmesan on the potatoes during the final few minutes of baking for a crispy topping. For a Mediterranean take, add halved cherry tomatoes, olives, and a drizzle of extra-virgin olive oil before sealing the packets.

This foil-baked cod with potatoes and lemon butter is a comforting, flavorful dinner that’s easy to love: simple ingredients, concentrated flavor, and almost no cleanup. It’s an excellent go-to for busy weeknights or a relaxed weekend meal.

Recipe: Baked Fish in Foil with Potatoes

Serves: 4 • Prep: 20 mins • Cook: 45 mins • Total: ~1 hour

Ingredients

• 1 1/2–2 lb fresh cod, cut into four pieces
• 3 medium yellow potatoes, thinly sliced
• 5 tbsp unsalted butter (or vegan butter to make dairy-free)
• 1 lemon, sliced
• Sea salt and black pepper, to taste
• Fresh thyme sprigs

Instructions

1. Preheat the oven to 425°F (220°C). Line a large baking sheet with four pieces of heavy-duty aluminum foil.
2. Slice potatoes about 1/8–1/4 inch thick. Melt 2–3 tablespoons of the butter and toss the potato slices briefly to coat. Arrange overlapping potato slices on each piece of foil to form four small “beds.” Season with sea salt and tuck a few thyme leaves on top. Bake the potato beds 20–25 minutes, until they begin to soften and the edges start to brown.
3. While the potatoes are baking, cut the cod into equal portions, brush with the remaining melted butter and season with salt and pepper. Top each piece of fish with a lemon slice and a few thyme sprigs.
4. Place a piece of seasoned cod on each potato bed. Fold up the foil sides to form a loose packet or pocket, leaving a little room for steam to circulate but sealing the edges well enough to hold juices.
5. Return the packets to the oven and bake 18–20 minutes, or until the fish flakes easily with a fork. Cooking time varies slightly with thickness — thicker fillets may need a few extra minutes.
6. Open the foil carefully (watch for steam) and serve each portion with an extra squeeze of lemon, a sprinkle of fresh herbs, and a green salad or steamed vegetable on the side.

Notes

• If one end of a fillet is much thinner than the other, fold the thin end under to create an even thickness so the fish cooks uniformly.
• For a crisper potato edge, slide the packets open for the last 3–5 minutes of baking. For dairy-free, use vegan butter or a splash of olive oil.