Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy

By , Test Kitchen Director · Reviewed by AislePrompt Editorial · ·

Tender pan-seared Lake Superior whitefish fillets served alongside creamy mashed potatoes topped with savory onion gravy. This american-inspired seafood ready in about 55 minutes pairs salt, black pepper, unsalted butter for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 450 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 20 min Cook: 35 min Serves 4 American cuisine 450 cal/serving
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Ingredients

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Instructions

  1. Step 1: Peel and cut 2 lbs russet potatoes into 2-inch chunks. Place in a large pot with 3 peeled garlic cloves and cover with cold water. Bring to a boil over high heat and cook for 15-18 minutes until tender when pierced with a fork.
  2. Step 2: Drain potatoes and garlic and return to pot. Add 1 cup whole milk and 2 tbsp unsalted butter, then mash until smooth and creamy. Season with 1/2 tsp salt and 1/4 tsp black pepper; keep warm.
  3. Step 3: Season 4 Lake Superior whitefish fillets evenly with 1 tsp salt and 1/2 tsp black pepper. Heat 2 tbsp olive oil and 1 tbsp unsalted butter in a large skillet over medium-high heat until shimmering.
  4. Step 4: Add the fillets skin-side down and cook for 4-5 minutes until the edges are crispy and golden. Flip carefully and cook an additional 2-3 minutes until fish is opaque and flakes easily. Remove fish and keep warm.
  5. Step 5: In the same skillet, reduce heat to medium and add 2 tbsp unsalted butter. Add 1 large thinly sliced yellow onion and sauté for 8-10 minutes until soft and caramelized.
  6. Step 6: Stir in 2 tbsp all-purpose flour and cook for 1 minute, stirring continuously to remove raw flour taste.
  7. Step 7: Gradually whisk in 2 cups beef broth and add 2 sprigs fresh thyme. Simmer for 5-7 minutes until gravy thickens and coats the back of a spoon. Remove thyme sprigs.
  8. Step 8: Serve the whitefish fillets over a bed of mashed potatoes, spoon the onion gravy generously over the top.

Frequently asked questions

How long does Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy take to make?

Total time is about 55 minutes (20 min prep + 35 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep salt from drying out.

Can I substitute ingredients in Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with Pan-Seared Lake Superior Whitefish with Mashed Potatoes and Onion Gravy?

American seafood like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

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