Rinse mussels under cold running water. Discard any with cracked shells or that remain open when tapped. Remove beards by pulling toward the hinge. Set aside on a tray in the refrigerator.

Sweat Aromatics

In a large, heavy-bottomed pot or Dutch oven, heat 1 tablespoon olive oil and 1 tablespoon butter over medium heat until shimmering. Add minced shallots and cook, stirring, until softened and translucent, about 2–3 minutes. Add minced garlic and cook 30–45 seconds more until fragrant.

Add Wine and Herbs

Pour in 1 cup dry white wine, add the bay leaf and thyme, and bring to a simmer. Let the wine reduce slightly for 2 minutes to concentrate flavor.

Steam Mussels

Increase heat to high, add the cleaned mussels to the pot, cover with a tight-fitting lid, and steam for 4–6 minutes, shaking the pot once or twice, until the mussels have opened. Discard any mussels that remain closed after cooking.

Finish Sauce

Remove mussels with a slotted spoon into a warmed serving bowl, leaving the cooking liquid in the pot. Reduce the liquid over medium-high heat if it seems too thin, about 1–2 minutes. Swirl in the remaining 2 tablespoons butter, lemon zest and juice from 1 lemon, chopped parsley, and season with 1 tsp salt and 1 tsp freshly ground black pepper. Taste and adjust seasoning. Pour the sauce over the mussels or serve alongside.

Frites (Fries)

Prep Potatoes

Cut peeled russet potatoes into 1/3–1/2-inch matchsticks. Place cut potatoes into a large bowl of cold water; add 1 tablespoon white vinegar if using. Soak for 30 minutes to remove excess starch (or at least 15 minutes).

Dry and Blanch (First Fry)

Drain the potatoes and rinse under cold water until water runs clear. Thoroughly dry the fries on clean kitchen towels or paper towels. Heat 1 cup vegetable oil in a heavy skillet or deep pan to about 325°F (160°C). If you don’t have a thermometer, heat until oil shimmers but isn’t smoking. Fry potatoes in batches (do not overcrowd) for 3–4 minutes until softened but not browned. Remove with a slotted spoon and drain on paper towels. Let cool for 5–10 minutes.

Crisp (Second Fry)

Increase oil temperature to 375°F (190°C) — use canola or peanut oil for this stage. Fry the blanched fries in batches for 2–3 minutes until golden and crisp. Remove and drain on paper towels, immediately sprinkle with fine sea salt.

Keep Warm

If serving immediately, place finished fries in a single layer on a baking sheet in a 200°F (95°C) oven to keep warm and crisp while you finish mussels.

Garlic Mayonnaise (Aioli)

Combine 1/2 cup mayonnaise, 1 minced garlic clove, 1 teaspoon lemon juice, 1/2 teaspoon Dijon mustard, 1/4 teaspoon salt, and 1/4 teaspoon black pepper in a small bowl. Whisk until smooth and refrigerate until ready to serve. Taste and adjust acid or seasoning if needed.

Garnish / Finish

Scatter 1 tablespoon chopped parsley over the mussels and place lemon wedges on the side. Serve mussels steaming in their bowl with the frites and a small ramekin of garlic mayonnaise. Provide crusty bread if desired to mop up the sauce.