Smoked Haddock with Buttered Spinach

This restaurant-worthy smoked haddock with buttered spinach and mustard sauce transforms a handful of fresh ingredients into a comforting and elegant meal that feels just right for a cozy weekend dinner or a relaxed dinner party. The delicate smokiness of the fish, creamy mustard sauce, and tender spinach come together faster than you might imagine and create something truly special.

The very first time I cooked this for my spouse on a rainy night I remember being amazed that something so easy could be so luxurious. The combination of flaky smoked fish with a sauce that takes minutes has made it a repeat request at our table.

Ingredients

• Smoked haddock fillets: You want fillets that feel firm and have a pleasant smoky scent. Look for undyed fish for the cleanest flavor and check for pin bones before cooking
• Fresh spinach: Bright green fresh spinach cooks down to a creamy bed beneath the fish. Young spinach leaves wilt faster and taste sweeter
• Butter: Adds richness to the spinach. Use real butter for the best finish
• Shallot: Finely chopped shallots gently sweeten and perfume the buttered spinach. Seek out firm bulbs with no soft spots
• Garlic: Fresh minced cloves bring aromatics and depth to the spinach. Always choose garlic that feels heavy for its size
• Heavy cream: Essential for the silky mustard sauce. Look for cream with a high fat content for the richest result
• Dijon mustard: Gives the sauce its signature tang and complexity. Choose a smooth high quality Dijon for best balance
• Salt and pepper: Balances and brightens all the flavors. Use flaky salt if you have it and freshly cracked black pepper

Step-by-Step Instructions

Prep and Bake the Haddock:

Pat the smoked haddock fillets dry with paper towels and lay them in a lightly greased baking dish. Sprinkle with just enough salt to highlight their flavor and a few turns of black pepper. Bake the fish in a preheated 375 degree oven for 15 to 20 minutes. You are looking for the fish to become opaque throughout and for it to flake easily when nudged with a fork

Sauté the Aromatics:

In a large skillet melt the butter slowly over medium heat until just beginning to foam. Add finely chopped shallot and minced garlic to the pan. Cook gently stirring often for about three minutes until the shallot is glassy and the garlic is no longer raw. Do not let the mixture brown as you want the flavors to stay mellow and sweet

Wilt the Spinach:

Pile the fresh spinach into the skillet with the shallots and garlic. Use tongs to toss and turn the leaves as they collapse and turn glossy green. Continue cooking another two to three minutes just until the spinach is wilted and any excess moisture is mostly evaporated. Taste and season with another light pinch of salt and pepper

Make the Mustard Sauce:

Pour the heavy cream into a separate small saucepan and set it over low heat. Stir in the Dijon mustard making sure it fully incorporates. Warm the sauce until it begins to thicken slightly which should only take several minutes. Watch closely and stir often so the cream does not scorch or become too thick. You want a pourable luxurious consistency

Assemble and Serve:

Spoon the warm glossy spinach onto individual plates letting it form a soft bed. Gently set a baked smoked haddock fillet on top of each mound of spinach. Drizzle each portion with a generous amount of the creamy mustard sauce making sure every bite gets some of the tangy richness. Serve immediately while everything is hot

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I honestly never get tired of how quickly the mustard cream sauce comes together. It might be my favorite part of the whole dish and I have used it over steamed vegetables too. My kids once helped assemble their own plates and seeing their faces light up tasting the sauce was a highlight for me.

Storage Tips

If you have leftovers allow the fish and spinach to cool to room temperature first before storing. Place them in separate airtight containers to keep the spinach from getting soggy. The creamy mustard sauce can be refrigerated in a small jar. When reheating use gentle heat for the fish and sauce and quickly warm the spinach in a pan to help retain its texture. If assembled together leftovers will keep for up to two days in the fridge though the sauce may separate slightly.

Ingredient Substitutions

If you cannot find smoked haddock try smoked cod which is quite similar in texture and flavor. For the greens kale or chard can replace spinach but make sure to cook them a little longer and chop them finely. If you need a dairy free version use a quality plant based cream and swap butter for olive oil. The Dijon mustard is traditional but a wholegrain mustard will give a slightly different texture and extra pops of flavor.

Serving Suggestions

I like to pair this dish with crusty bread or buttered boiled potatoes to absorb every last drop of sauce. A lemon wedge on the side adds brightness and rounds out the flavors. For a more formal meal serve alongside steamed asparagus or a simple green salad. The colors and flavors make this a wonderful centerpiece for a family lunch or a cozy Sunday supper.

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Enjoy a meal that feels both comforting and luxurious with minimal effort.

Frequently Asked Questions

→ What type of haddock is best for this dish?

Cold-smoked haddock fillets are ideal, as they bring a distinct smoky flavor and hold up well during baking.

→ Can I substitute another green for spinach?

Yes, Swiss chard or kale can work well, though cooking times may need slight adjustments for tenderness.

→ How can I ensure the fish doesn't dry out?

Bake the haddock just until it flakes easily with a fork and cover loosely with foil if needed to retain moisture.

→ Is it possible to make the mustard sauce ahead of time?

The sauce may be prepared in advance and gently reheated before serving, stirring to maintain a smooth texture.

→ What sides pair well with this combination?

Steamed potatoes or a crusty bread complement the flavors, soaking up the creamy mustard sauce beautifully.