Fish Pie Recipe With Mashed Potato Topping: Flaky Fish and Creamy Mash Harmony

There’s something deeply comforting about a well-made fish pie with its flaky fish and creamy mashed potato topping. This dish combines the best of both worlds—tender fish in a rich sauce, crowned with a blanket of velvety potatoes.

What makes this recipe special is the balance of textures. The fish stays moist and tender while the mashed potato topping bakes to a golden finish. It’s a meal that feels indulgent without being overly complicated.

I’ve perfected this version after testing different fish combinations and seasoning blends. The result is a pie that’s hearty, satisfying, and perfect for a cozy dinner.

Serve it straight from the oven for the best experience. Here’s how to make it.

Ingredients for Fish Pie Recipe with Mashed Potato Topping

Velvety potatoes, flaky fish, and a rich sauce come together in this ultimate comfort dish.

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The fish is the star here. Wild-caught cod or haddock from Whole Foods or your local fishmonger gives the best flaky texture—avoid pre-frozen if possible. For the salmon, skinless center-cut fillets work best. Russet potatoes are ideal for that ultra-creamy mash (their high starch content can’t be beat). Organic heavy cream from Trader Joe’s adds that luxurious finish to the sauce.

No cod or haddock? Pollock or halibut work beautifully. Swap the salmon for trout or sea bass if that’s what’s fresh. Fresh peas instead of frozen? Even better (just blanch them first). For a lighter version, half-and-half instead of heavy cream still delivers great flavor. The Dijon mustard can be swapped for whole-grain mustard for a rustic touch.

The mashed potato topping can be made 2 days ahead—store covered in the fridge. Assemble the pie just before baking. Leftovers keep well for 3-4 days and reheat beautifully. For the best texture, warm covered in the oven at 350°F until heated through (microwaving can make the potatoes gummy).

Step-by-Step Instructions for Fish Pie With Mashed Potato Topping

Here’s the method to create this flaky, creamy masterpiece with perfect layers every time.

Step 1: Prepare the Mashed Potato Topping

Place the 2 lb Russet Potatoes in a pot and cover with cold water. Bring to a boil over high heat, then reduce to medium and cook for 15-20 minutes until a knife slides in easily. Drain thoroughly—any excess water will make your topping gluey.

Return the potatoes to the pot and mash with the 0.5 cup Whole Milk and 0.5 cup Unsalted Butter. Season with 1 tsp Kosher Salt and 0.5 tsp Ground Black Pepper until smooth. The texture should be creamy but firm enough to hold its shape when piped or spread over the filling.

Step 2: Sauté the Aromatics for the Filling

In a large skillet, melt 2 tablespoons of the Unsalted Butter over medium heat. Add the finely diced Yellow Onion and cook for 5 minutes until translucent and sweet. Stir in the minced 3 cloves Garlic Cloves and cook for 1 minute until fragrant.

Add the 0.25 cup All-Purpose Flour and stir constantly for 1-2 minutes to cook out the raw flour taste. This creates a roux that will thicken your sauce beautifully. Watch for the mixture to turn a light golden color—it should smell nutty and toasted.

Step 3: Build the Creamy Fish Filling

Gradually whisk in the 1 cup Chicken Stock and 1 cup Heavy Cream until smooth. Stir in the 1 tbsp Dijon Mustard, 1 tbsp Lemon Juice, and 0.5 tsp Kosher Salt. Simmer for 3-4 minutes until the sauce thickens enough to coat the back of a spoon.

Gently fold in the 1.5 lb White Fish Fillets, 0.5 lb Salmon Fillet (cut into chunks), and 1 cup Frozen Peas. Cook for 2-3 minutes just until the fish begins to flake—it will finish in the oven. The fish should look opaque and tender, not rubbery.

Step 4: Assemble and Bake to Perfection

Transfer the fish filling to a baking dish and spread it evenly. Top with the mashed potatoes, using a fork to create textured peaks that will crisp up in the oven. This step ensures a beautiful golden finish and maximum surface area for browning.

Bake at 400°F for 20-25 minutes until the topping is golden brown and the filling is bubbling at the edges. For extra color, broil for 1-2 minutes at the end, but watch it closely to avoid burning.

Step 5: Rest and Garnish Before Serving

Let the pie rest for 5-10 minutes after removing it from the oven. This allows the filling to set slightly, making it easier to serve neat portions. The topping should be firm but still tender underneath, with a rich, creamy sauce peeking through.

Garnish with the 0.25 cup Fresh Parsley just before serving. Each bite should deliver flaky fish, creamy sauce, and a perfectly buttery mashed potato topping that holds together just enough to be scooped up with a spoon.

Flavor Customization for fish pie recipe with mashed potato topping

Herb Infusions

Add 2 tbsp fresh dill or 1 tbsp dried tarragon to the creamy filling for a bright, aromatic lift. I love how dill pairs with salmon—it reminds me of summer days at Nana Mae’s diner. 🌿

Cheesy Topping

Mix ½ cup shredded cheddar or ¼ cup grated Parmesan into the mashed potatoes before baking. The cheese melts into the topping, creating a golden, savory crust.

Spicy Kick

Stir ½ tsp cayenne or 1 tsp smoked paprika into the filling for warmth. David, my taste-tester, swears by this tweak for a little extra heat.

Citrus Zest

Add 1 tsp lemon zest to the mashed potatoes for a subtle citrus note. It brightens the richness of the dish without overpowering the fish.

Creamy Additions

Fold ½ cup cooked shrimp or ¼ cup chopped scallops into the filling for a seafood medley twist. This works especially well when using Central Market’s fresh seafood. 💛

Crispy Breadcrumbs

Sprinkle ¼ cup panko breadcrumbs mixed with 1 tbsp melted butter over the mashed potatoes before baking. This adds a delightful crunch to every bite.

Frequently Asked Questions