Butter Poached Halibut Recipe

Cook potatoes

Place cubed potatoes in a medium saucepan and cover with cold salted water by about 1 inch. Bring to a simmer over medium-high heat and cook until potatoes are tender when pierced, about 12–15 minutes.

Drain and mash

Drain potatoes thoroughly and return to the warm pot over low heat for 1 minute to dry out any excess moisture. Mash or pass through a ricer until smooth.

Finish purée

Stir in 3 tablespoons butter, then gradually add warm milk or cream until the purée reaches a smooth, silky consistency (you may not need all the liquid). Season with 3/4 tsp salt, 1/4 tsp white or black pepper and 1/2 tsp lemon zest if using. Keep warm on very low heat, stirring occasionally.

Sauté leeks and fennel

Heat 1 tablespoon olive oil in a skillet over medium heat. Add the sliced leeks and fennel and sauté, stirring occasionally, until softened and beginning to caramelize, about 6–8 minutes. Season with 1/2 tsp salt and 1/4 tsp pepper.

Add tomatoes & finish

Add halved cherry tomatoes and cook 2–3 minutes just until they warm and release some juices but still hold shape. Remove from heat and stir in 1 teaspoon lemon juice. Keep warm.

Prepare butter and aromatics

In a wide, shallow sauté pan or skillet large enough to hold the fillets in a single layer, combine 1 cup butter, 1 cup white wine, 1 cup stock, crushed garlic, thyme sprigs and bay leaf. Bring gently to a bare simmer over low-medium heat, allowing the butter to melt and the liquid to come to about 185–195°F (do not boil). Season the liquid with 1 tsp salt and 1 tsp freshly ground pepper.

Clarify slightly (optional)

If you prefer a clearer poaching liquid, skim any foam or milk solids from the surface once the butter has fully melted and the liquid is steady at a low simmer.

Poach the halibut

Reduce heat to low so the liquid is barely moving (small bubbles around the edge). Submerge the halibut fillets in the butter-wine liquid in a single layer. Poach gently until opaque and the center reaches 125–130°F (about 6–10 minutes depending on thickness). Spoon the warm butter liquid over the fillets occasionally to keep them evenly cooked. Remove fillets with a slotted spatula and transfer to a warm plate; tent loosely with foil to rest for 2 minutes.

Reduce poaching liquid to sauce (optional)

Increase heat to medium and simmer the remaining poaching liquid until slightly thickened and reduced by about one-third, about 5–7 minutes. Taste and adjust seasoning. Strain if desired, then whisk a small knob (about 1 tablespoon) of cold butter into the hot sauce off the heat to gloss it, if you want an extra-silky finish.

Place a generous spoonful of warm potato purée in the center of each plate and smooth into a shallow well. Spoon a portion of the warm leek–fennel–tomato mélange beside or over the purée.

Lay a butter-poached halibut fillet on top of the purée. Spoon some of the reduced butter-wine sauce around the fish and over the vegetables (reserve a little sauce to drizzle).

Garnish with chopped fennel fronds, a light drizzle of extra-virgin olive oil, and microgreens or parsley. Serve immediately.