Fish and Potatoes Recipe: One-Pan Herb-Roasted Harmony

This one-pan herb-roasted fish and potatoes recipe transforms simple ingredients into a restaurant-worthy meal with minimal effort. The secret lies in balancing tender fish with perfectly crispy potatoes, all seasoned to harmonize on one sheet pan.

I developed this method after years of struggling with separate cooking times—now, everything comes together in 45 minutes with just one pan to clean.

The foundation starts with firm white fish like cod or halibut, cut into even portions to cook uniformly alongside baby potatoes that develop crispy edges while staying tender inside.

A blend of fresh herbs—thyme, rosemary, and parsley—infuses both components with bright, aromatic flavor without overpowering the natural taste of the fish. The key technique? Roasting the potatoes first at high heat to render their natural oils, then adding the fish to finish together.

What you’ll end up with is a plate that looks as impressive as it tastes: golden, crispy potatoes with tender fish fillets resting atop, their edges just flaking apart. The herbs release their fragrance as they roast, creating an inviting aroma that fills your kitchen.

This dish works equally well for weeknight dinners or weekend gatherings, with optional sides like a simple green salad or steamed vegetables to complete the meal.

Ready to master this foolproof one-pan technique? The instructions walk through every step—from prepping the potatoes to timing the fish—so you’ll achieve professional results without the fuss. Let’s get cooking.

Ingredients for fish and potato

Simple yet sophisticated ingredients that harmonize on one sheet pan for restaurant-quality results.

The quality of your fish and potatoes makes all the difference. For the fish, look for cod fillets with bright, translucent flesh—avoid any with brown edges or a fishy odor. Whole Foods or local seafood markets typically carry the freshest cuts; if grocery shopping, check the seafood case last for maximum freshness. Baby potatoes should be firm and uniform in size—Yukon Golds develop a creamy interior while red potatoes stay crispier. Prep them by boiling for 8 minutes to soften slightly before roasting. The herbs? Fresh is non-negotiable here—dried won't release the same aromatic punch. If you can't find fresh rosemary, substitute with 1/4 tsp dried, but it won't taste the same. Store fresh herbs wrapped in damp paper towels in a sealed container for up to 5 days.

No cod? Halibut or mahi-mahi work equally well—just adjust cooking time by 2-3 minutes. Running short on fresh herbs? Dried thyme and rosemary at 1/4 the amount will suffice, but toss in a pinch of dried parsley too. The lemon zest and juice are critical for brightness—substitute with 1 tbsp bottled lemon juice if fresh isn't available, but you'll lose some complexity. For the olive oil, avoid heavily perfumed varieties like garlic-infused—they can overpower the delicate fish flavor. If you're using pre-minced garlic, drain and dry it thoroughly to prevent excess moisture on the pan. The butter should be cold and cubed when added at the end to create a rich, glossy finish.

This dish reheats beautifully—cover with foil and warm at 350°F for 10 minutes to retain moisture. Store leftovers in an airtight container for up to 3 days, though the fish is best consumed within 2 days. For meal prep, roast an extra batch and portion into glass containers with parchment between layers to prevent sticking. The potatoes can be prepped ahead and stored in cold water in the fridge for up to 24 hours before roasting. Freezing isn't recommended for the fish, but you can freeze the herb mixture separately for up to 3 months—just thaw and re-chop before using.

Step-by-step instructions for one-pan herb-roasted fish and potatoes

This method delivers perfectly crisp cod and tender potatoes with aromatic herb layers—all on a single sheet pan.

Preheat your oven to 425°F while you prepare the potatoes. Rinse the 2 lb baby potatoes under cold water and scrub them clean with a vegetable brush, removing any dirt from their small crevices. Cut each potato into even 1-inch chunks—consistent size ensures uniform cooking throughout.

Place the potato pieces in a large mixing bowl and toss them with 0.25 cup extra-virgin olive oil, 1 tbsp lemon zest, and 1.5 tsp diamond crystal kosher salt. The zest adds a bright citrus note that complements the cod beautifully. Spread the seasoned potatoes on a parchment-lined rimmed baking sheet in a single layer, leaving about ½-inch between each piece for proper air circulation.

While the potatoes roast, prepare the 1.5 lb cod fillets for maximum crispiness. Pat each fillet dry with paper towels—moisture is the enemy of crispy skin. Arrange the cod skin-side down on the prepared baking sheet, spacing them evenly among the potatoes. This placement allows the potatoes to cook first while the cod rests above, preventing it from steaming.

In a small bowl, combine 0.25 cup fresh thyme leaves, 0.125 cup finely chopped fresh rosemary, 0.125 cup fresh parsley, 0.5 tsp ground black pepper, and 4 minced garlic cloves. Sprinkle half of this herb mixture evenly over the potatoes, reserving the rest for later. The aromatic herbs will infuse the potatoes with deep, earthy flavors while the cod cooks.

Transfer the baking sheet to the preheated oven and roast for 20 minutes. After this initial period, carefully flip the cod fillets using a fish spatula—gently slide the spatula under each fillet to avoid tearing the delicate flesh. Sprinkle the remaining herb mixture over the cod and potatoes, then return the sheet to the oven.

Continue roasting for another 12-15 minutes until the potatoes are golden brown and tender when pierced with a fork, and the cod reaches an internal temperature of 145°F. The skin should be crisp and the flesh should flake easily with a fork. If the cod begins to brown too quickly, tent it loosely with aluminum foil to prevent overcooking.

Remove the baking sheet from the oven and transfer the cod fillets to a serving platter. In a small saucepan, melt the 2 tbsp unsalted butter over low heat and stir in the 2 tbsp fresh lemon juice. Simmer for 1 minute until the butter is fragrant and slightly emulsified. Pour this lemon butter evenly over the cod fillets.

Garnish the dish with additional fresh parsley and a sprinkle of flaky sea salt for brightness. Serve the potatoes directly from the baking sheet, allowing guests to scoop them up with the cod. The potatoes should be tender with crisp edges, infused with lemon and herbs, while the cod remains moist and flaky with a delicate crispness on the skin.

Essential equipment for this recipe

Sheet Pan Essentials

Your half-sheet pan is the star of this recipe—I recommend a 17x11-inch heavy-duty pan like All-Clad Stainless Steel for even heat distribution. The pan must have 2-inch sides to prevent spills when flipping the cod.

For budget-friendly options, Ozeri 17x11-inch pans work well and are dishwasher-safe. Line with parchment paper for easy cleanup, but leave the edges exposed for crispy potatoes. 🔥

Temperature Gauges

An instant-read thermometer is non-negotiable for perfect cod—ThermoWorks ThermoPop is my go-to for accuracy. Insert the probe into the thickest part of the fillet to check for 145°F internal temperature.

For potatoes, test with a fork—they're done when tender with crisp edges. A dual-probe thermometer like Meater lets you monitor both components simultaneously for foolproof results.

Herb Prep Tools

Fresh herbs need proper prep for maximum flavor. A microplane is perfect for lemon zest, while a sharp chef's knife and cutting board (I love Shun Premier) handle the herbs. For mincing garlic, a garlic press saves time, but a knife works too—just drain the excess liquid.

Store herbs in glass containers with damp paper towels to maintain freshness. A herb scissor like OXO Good Grips makes snipping thyme and parsley effortless.

Butter Finishing

The lemon butter sauce requires precise control. Use a small saucepan (I prefer Le Creuset 1.5-quart) and low heat to melt 2 tbsp unsalted butter without burning. A whisk helps emulsify the sauce smoothly.

For extra shine, add 1 tsp cold water while whisking—this creates a silky finish. Keep a small bowl nearby to strain any solids if needed.

Flipping Tools

Cod is delicate, so use a fish spatula with a flexible silicone edge (like OXO Good Grips) to flip without tearing. Avoid metal spatulas—they can puncture the skin. For extra grip, lightly wet your fingers before handling.

A tongs with siliconized tips works too, but practice makes perfect for clean flips. Keep a small plate nearby to catch any loose herbs during transfers.

Frequently asked questions