Creamy Cod and Potato Gratin (Individual Portions)

Cod and potatoes are a timeless American pairing—from New England fish chowders to Midwestern Friday fish fries. This individual Creamy Cod and Potato Gratin celebrates that tradition with a restaurant-worthy presentation you can pull off in your home oven. Each portion starts with a cushion of mashed potatoes, topped with quick-simmered cod in a lemony cream sauce, finished with fresh tarragon (or dill) and a whisper of Parmigiano-Reggiano. After a brief bake, you’ll get a bubbling, crisp-edged topping with moist, flaky fish and a luscious sauce underneath.

The best part? The method is straightforward, uses supermarket staples, and adapts easily for small households or larger gatherings. Whether you’re planning a cozy date night, a special Sunday supper, or simply want to elevate your seafood routine, this cod gratin delivers comfort, elegance, and reliability.

Why This Creamy Cod and Potato Gratin Recipe Works

• Cream-on-cream balance: Russet potatoes make a fluffy, absorbent base that soaks up the sauce without turning watery. The lemon zest and juice in the cream keep richness in check, so each bite tastes bright, not heavy.
• Two-stage sauce: A quick stovetop simmer infuses shallot, citrus, and cayenne into the cream before the oven bake, building depth in minutes. Reducing the leftover sauce briefly concentrates flavor and ensures a clingy, velvety texture.
• Individual gratins = perfect doneness: Small, shallow dishes heat quickly, so the cod gently steams in sauce and stays tender. The top browns while the fish remains moist.
• Smart herb choice: Tarragon adds a delicate anise note that loves both cream and seafood; dill offers a fresh, coastal vibe. Either herb makes the dish taste light and modern.
• High heat, short bake: A hot oven (450°F) gives you a golden, gratinéed finish fast—ideal for preserving the cod’s juiciness.

Ingredients For The Creamy Cod and Potato Gratin

• 2 medium russet potatoes, peeled and quartered
• 2 cod fillets (6 to 8 ounces each), trimmed and cut into 2-inch pieces
• 2 pinches cayenne pepper, divided (or to taste)
• Kosher salt, to taste
• 7 tablespoons unsalted butter, divided
• 2 tablespoons finely chopped shallot
• 1 cup heavy cream
• 2 teaspoons lemon zest
• 1 tablespoon fresh lemon juice
• 1 tablespoon chopped fresh tarragon (or substitute dill)
• 2 teaspoons freshly grated Parmigiano-Reggiano (or to taste)

Yield: 2 individual gratins

Notes and smart swaps for American kitchens:

• Potatoes: Russets whip up light and absorbent. In a pinch, use Yukon Golds for a naturally buttery texture (they’ll be a touch denser).
• Fish: Fresh or previously frozen cod loins are ideal. Haddock, pollock, or hake are great regional substitutes if cod is unavailable.
• Dairy: Half-and-half works if you prefer a lighter sauce; just reduce an extra minute to thicken.
• Heat: Cayenne is optional; a pinch keeps the dish lively without tasting spicy.
• Cheese: Parmigiano-Reggiano gives a savory finish. Pecorino Romano is sharper and saltier—use a lighter hand.

Step-by-Step Creamy Cod and Potato Gratin Instructions

1. Prepare the potatoes

• Place the peeled, quartered russets in a large pot of well-salted cold water.
• Bring to a boil, then simmer gently until tender, about 20 minutes.
• Drain well and return to the pot over low heat for 30–60 seconds to steam off excess moisture.
• Mash with 4 tablespoons butter, 1 pinch cayenne, and salt to taste until smooth and fluffy.

2. Prepare the cod and sauce

• Preheat the oven to 450°F (230°C). Butter two individual gratin or small casserole dishes with 1 tablespoon butter total, and place them on a baking sheet.
• In a large skillet over medium-high heat, melt 2 tablespoons butter. Add shallot and a pinch of salt; cook 3–4 minutes until translucent with light golden edges.
• Stir in heavy cream, lemon zest, and a pinch of cayenne; bring to a gentle simmer.
• Add the cod pieces; cook 2 minutes, turning once so the fish just starts to turn opaque at the edges.
• Remove from heat, stir in lemon juice, and let rest 30 seconds to settle.

3. Assemble the gratins

• Spoon about 2/3 cup mashed potatoes into each buttered dish; smooth and make a shallow well.
• Nestle cod pieces on top and ladle over enough sauce to cover.
• Return the skillet to medium-high heat and reduce any remaining sauce 1–2 minutes until slightly thickened; stir in chopped tarragon (or dill).
• Spoon this concentrated sauce over the gratins and dust each with Parmigiano-Reggiano.

4. Bake and serve

• Bake on the center rack at 450°F until tops are golden and sauce is bubbling, 10–15 minutes.
• Rest 5 minutes to allow the sauce to set. Serve warm.

Food-safety note: Fish is considered fully cooked when it flakes easily with a fork and reaches an internal temperature of 145°F in the thickest part. If you cook by temp, check quickly so you don’t overbake.

Pro Tips for Best Creamy Cod and Potato Gratin Results

• Dry potatoes = fluffy mash: After draining, briefly return potatoes to warm pot to evaporate moisture.
• Season in layers: Salt the potato water, the shallots, and the mash. Balanced seasoning means fewer last-minute fixes.
• Watch the simmer: Keep cream at a gentle bubble to avoid scorching and to thicken evenly.
• Use bright lemon: Zest brings aromatic citrus oils; don’t skip it. The juice goes in off heat to stay fresh-tasting.
• Size matters: Two-inch fish pieces cook evenly and fit neatly into individual dishes.
• Golden top hack: If you want a deeper gratin color, switch to broil for the last 45–60 seconds. Watch closely.

What to Serve with Creamy Cod and Potato Gratin

• Crisp greens: A simple arugula or mixed-green salad with lemon vinaigrette keeps the plate light.
• Green vegetables: Roasted asparagus, sautéed green beans with almonds, or garlicky broccolini.
• Something pickled: A few cornichons or pickled red onions brighten richness.
• White wine: Try a cool-climate Chardonnay, Pinot Blanc, or a dry Riesling.
• For a cozy American touch: Warm dinner rolls or a slice of sourdough to swipe through the sauce.

Make-Ahead, Storage, and Reheating

• Make-ahead components:
  • Mashed potatoes can be prepared 1–2 days ahead. Store covered in the fridge; rewarm gently with a splash of cream or milk before assembling.
  • Shallots can be chopped a day in advance and refrigerated.
• Assemble ahead: You can assemble the gratins (with cooled mash and cooled sauce) up to 4 hours before baking. Cover and refrigerate. Add 3–5 extra minutes to the bake time since they’ll start cold.
• Storage: Leftover baked gratins keep 1–2 days in an airtight container in the refrigerator.
• Reheating: Reheat at 325°F, covered, until warmed through, 12–15 minutes for individual dishes. Add a spoonful of cream to keep things silky. Avoid microwaving if possible; it can overcook the fish.
• Freezing: Not recommended. Cream sauces can separate and potatoes can turn grainy after thawing.

FAQs

• Can I use frozen cod?
  Yes—thaw overnight in the fridge and pat very dry before cooking so the sauce doesn’t thin out.
• What fish can replace cod?
  Haddock, pollock, hake, or even halibut work well. Choose mild, flaky white fish with similar thickness.
• Do I need special gratin dishes?
  Any small oven-safe dishes (12–16 ounce capacity) work: mini casseroles, large ramekins, or small cast-iron skillets. You can also triple the recipe and bake in a 9×13-inch dish for family-style serving; extend baking by a few minutes.
• Can I make it gluten-free?
  The base recipe is naturally gluten-free—no flour needed. Just confirm your cheese and any sides are GF.
• Is the cayenne spicy?
  It’s a gentle, warming pinch that brightens the cream. Add more if you like heat, or omit for zero spice.
• How do I know the cod is done?
  It should flake easily and look opaque throughout. If using a thermometer, aim for 145°F in the thickest piece.
• Will dill taste as good as tarragon?
  Different, but equally delicious. Dill skews fresh and coastal; tarragon reads elegant and aromatic. Choose your vibe.

Serving & Storage (Quick Reference)

• Serve: After a 5-minute rest so the sauce thickens slightly.
• Store: Refrigerate 1–2 days.
• Reheat: 325°F, covered, until hot; moisten with a splash of cream if needed.
• Not freezer-friendly.

Chef’s Notes for American Cooks

• Lemon is a must: It cuts through cream and complements sweet, flaky American cod.
• Season your mash like you mean it: Properly salted potato water is the difference between bland and “restaurant good.”
• Don’t skimp on resting time: Five minutes post-bake helps the gratin set and eat more luxuriously.
• Crowd-pleaser move: Build a larger casserole for gatherings, then scoop into warm bowls. It’s comfort food with a dressed-up finish.

 

Why You’ll Love This Creamy Cod and Potato Gratin

• Elegant comfort food: All the cozy, creamy goodness you crave—presented in individual bubbling gratins.
• Easy to customize: Swap tarragon for dill, adjust the cayenne, or size up to a family casserole.
• Simple ingredients, big flavor: Cod, potatoes, cream, lemon, and herbs—everyday staples that deliver restaurant-quality results.
• Weeknight friendly: Short stovetop simmer plus a quick high-heat bake gets dinner on the table without fuss.
• Dinner-party ready: Individual portions look special and keep serving effortless.

Final Thoughts

If you love classic American seafood comfort but want a dish that also feels polished, this Creamy Cod and Potato Gratin is the sweet spot. Silky mashed potatoes, succulent cod, and a lemon-kissed cream sauce meet in a golden, bubbling package that’s as impressive as it is comforting. Keep it simple with a crisp green salad and a squeeze of lemon, or pair it with roasted asparagus and chilled white wine for a full-on bistro moment at home. However you serve it, this cod gratin is poised to become a new favorite—dependable for weeknights, dazzling for guests, and always deeply satisfying.

Hungry for more? Explore related seafood recipes and sides on your site to round out a complete, crowd-pleasing menu.