Prepare the Potatoes: Wash the potatoes thoroughly and cut them into halves or quarters. Place them in a pot of salted boiling water and cook for 8–10 minutes until fork-tender. Drain and set aside.
Season the Cod: Pat the cod fillets dry with paper towels. Season each fillet with salt, pepper, lemon juice, and lemon zest. Let the fillets marinate briefly while preparing the pan.
Sear the Cod: Heat 2 tablespoons olive oil and 1 tablespoon butter in a large skillet over medium-high heat. Place the cod fillets in the pan and sear for 3–4 minutes per side until lightly golden and cooked through. Remove the fillets from the pan and set aside on a warm plate.
Sauté the Aromatics: In the same skillet, reduce heat to medium. Add olive oil, garlic, and shallots. Cook for 2–3 minutes until fragrant and translucent. Stir in chopped rosemary and sauté for another minute.
Add Broth and Cream: Pour in the halal-certified broth and bring to a gentle simmer. Stir in the heavy cream and Dijon mustard if using. Simmer for 6–8 minutes, stirring occasionally, until the sauce begins to thicken slightly.
Add the Potatoes: Return the boiled potatoes to the skillet and toss them gently in the cream sauce. Allow the potatoes to absorb some of the sauce and cook for an additional 3–4 minutes.
Return the Cod: Carefully place the seared cod fillets back into the skillet, spooning some of the sauce over each piece. Let everything simmer together for 2–3 minutes on low heat.
Finish and Serve: Garnish with freshly chopped parsley or chives if desired. Serve hot, plated individually or family-style, with crusty bread or a side salad.
