Flaky baked cod and tender baby potatoes are smothered in a creamy mustard sauce with capers and plenty of fresh herbs. It sounds fancy, but it’s easy: the oven does most of the work and the mustard cream sauce is whisked together in a bowl—no stovetop required. About 10 minutes of prep and dinner practically makes itself.
Cozy, creamy, and ready in under an hour
- This is a great transitional dinner—warmer than a salad but lighter than winter stews. The fresh herbs and briny capers give it a bright spring or summer edge.
- Everything bakes in one dish, which makes this recipe very weeknight-friendly. If you prefer less mustard, reduce the amount in the sauce to one-half or one-quarter and you’ll still have a silky cream with a gentle mustard note.
- Mustard fans will especially love the mustard-forward cream sauce: creamy, tangy, and rich. It pairs beautifully with crusty bread for sopping up the sauce.
My serving recommendation
Tear off pieces of crusty sourdough to soak up the sauce and finish the meal with a chilled glass of white wine. This dish feels special but truly takes minimal effort.
Ingredients
Here are the components for the fish, potatoes, mustard cream sauce, and garnish. Quantities match a 4-serving batch.
For the fish and potatoes
- 3 tablespoons olive oil
- 1 tablespoon Old Bay seasoning
- 1 teaspoon rubbed sage
- Kosher salt and freshly cracked black pepper
- 1.5 pounds baby gold potatoes
- 1 pound cod fillet
For the mustard cream sauce
- 3/4 cup heavy cream
- 1/4 cup chicken broth
- 1/4 cup capers
- 2 cloves garlic, finely minced
- 2 tablespoons Dijon mustard
- 2 tablespoons stone-ground mustard
- 1 tablespoon lemon juice
- Salt and freshly cracked pepper
Garnish
- Fresh chopped parsley
- Freshly sliced chives
- Lemon wedges
Notes on ingredients and substitutions
- Use this recipe as a blueprint—swap in another firm white fish or salmon if you prefer. Cooking time may vary slightly for thicker fillets.
- Baby gold potatoes roast to a creamy texture. If using larger potatoes, cut them into 1–1.5 inch chunks so they cook in the same timeframe.
- Both Dijon and stone-ground mustard are recommended: Dijon adds bright sharpness while stone-ground contributes texture and depth. Use less if you’re sensitive to mustard’s intensity.
- Any fresh, green herbs (dill, parsley, chives) will brighten the finished dish.
How it comes together
- Heat the oven. Preheat to 400°F (200°C).
- Mix the seasoning. In a small bowl, whisk together olive oil, Old Bay, rubbed sage, and a couple of large pinches of salt and pepper.
- Prep and par-bake the potatoes. Place potatoes in a 9×13 baking dish. Toss with about two-thirds of the seasoned oil so they’re evenly coated. Roast for 20–25 minutes until they are just tender but not fully cooked.
- Prepare the mustard cream sauce. While the potatoes roast, whisk heavy cream, chicken broth, capers, garlic, both mustards, lemon juice, and salt and pepper in a bowl until combined.
- Add the fish. Move the potatoes to the sides of the dish to create a well in the center. Pat the cod dry, brush both sides with the remaining seasoned oil, and nestle it into the center well.
- Pour on the sauce and finish baking. Pour the mustard cream sauce over the cod and potatoes, making sure the fish is coated. Return the dish to the oven and bake another 10–15 minutes or until the cod flakes easily and the potatoes are fork-tender.
- Garnish and serve. Finish with chopped parsley, sliced chives, and a squeeze of lemon. Serve immediately with bread for dipping if desired.
Tips from testing
- Combining Dijon and stone-ground mustard creates a balanced, textured sauce—don’t skip one or the other unless you must.
- If using one large fillet rather than individual portions, add a few extra minutes to the cook time and check for doneness with a fork.
- The dish may look quite saucy when it first goes in the oven, but the fish and potatoes absorb the sauce as they bake, leaving a perfect coating on each bite.
- Reduce mustard amounts to 1 tablespoon of each if you want a subtler mustard flavor.
Make-ahead and storage
- The mustard cream sauce can be mixed up to two days ahead and kept refrigerated; stir before using.
- Potatoes can be par-baked in advance. When ready to serve, add the fish and sauce and finish baking.
- Store leftovers in an airtight container in the refrigerator for up to three days. Reheat gently in a covered baking dish at 325°F until warmed through. Freezing is not recommended, as the cream sauce and fish texture degrade after freezing and thawing.
This one-dish baked fish and potatoes with mustard cream sauce is an approachable, flavorful weeknight meal that can be dressed up for guests or simplified for a quick family dinner. Enjoy the bright herb finish and the creamy, mustard-forward sauce that makes every bite memorable.