Begin by washing and cutting the baby or Yukon Gold potatoes into halves or quarters for even cooking. Bring a large pot of salted water to a boil, then add the prepared potatoes. Boil for 8–10 minutes until they are fork-tender but not falling apart. Drain the potatoes and set them aside, allowing them to steam off excess moisture while you prepare the sauce.

While the potatoes are cooking, take the cod fillets and pat them dry with a paper towel to remove moisture, ensuring a good sear. Season both sides of the fillets generously with salt, pepper, lemon juice, and zest for a bright flavor contrast. Set aside.

In a large skillet, heat olive oil and butter over medium-high heat. Once the butter is melted, carefully place the cod fillets in the skillet. Sear for 3–4 minutes on each side until golden brown and flaky. Transfer to a plate and cover to keep warm.

In the same skillet, reduce the heat to medium and add more olive oil if necessary. Add minced garlic and finely chopped shallots, sautéing for 2–3 minutes until they soften. Stir in chopped fresh rosemary, cooking for an additional minute.

Pour in broth, scraping up any bits from the bottom of the pan, then add heavy cream. Increase heat and bring to a gentle simmer, allowing to simmer for 6–8 minutes until thickened.

Introduce the drained potatoes back into the sauce, gently mixing to absorb flavors. Let soak for 3–4 minutes while stirring occasionally.

Carefully add the seared cod fillets back into the skillet. Spoon sauce over the top, allowing to warm for about 2–3 minutes on low.

Garnish with freshly chopped parsley or chives and serve hot with crusty bread or a side salad.