Creamy Gluten-Free Parsley Sauce Recipe

Gluten-Free Parsley Sauce is a simple, creamy accompaniment for fish, ham, pork chops or as a base for fish pie. This version uses cornflour (cornstarch) instead of wheat flour so it’s naturally gluten-free, and it’s brightened with plenty of fresh parsley, a touch of Dijon mustard, a splash of lemon and a little double cream for richness.

A traditional English parsley sauce is versatile and reliably easy to make. It pairs especially well with simply grilled buttered salmon for a quick weeknight meal, and it’s equally at home alongside glazed ham and mashed potatoes at holiday gatherings.

Does parsley sauce contain gluten?

Many classic parsley sauce recipes use a roux—butter combined with plain wheat flour—to thicken the sauce, and some ready-made mixes also contain wheat. This recipe avoids wheat entirely by using cornflour (cornstarch) as the thickening agent, producing a smooth, velvety gluten-free sauce.

Why you’ll love this recipe

• Effortlessly made from pantry staples plus fresh parsley.
• A traditional British white sauce that’s safe for gluten-free diets.
• Easily prepared ahead to simplify busy evenings.
• Fresh, balanced flavours — mustard and lemon lift the creamy base.

What is parsley sauce made of?

This is essentially a white sauce made with whole milk that’s been infused with fresh parsley, then thickened with cornflour and finished with cream, Dijon mustard, salt, white pepper and lemon juice.

Gluten-free thickener

Cornflour (cornstarch) is used here because it gives a light, smooth finish. If needed, tapioca starch or arrowroot are possible substitutes, though the texture will differ slightly.

Ingredients

• Whole milk — 500 ml. Substitute plant milk for a dairy-free version.
• Fresh parsley — about two large handfuls (roughly a 25–30 g bag), chopped.
• Cornflour (cornstarch) — 30 g.
• Dijon mustard — 1 teaspoon (use English mustard if you prefer more heat).
• Lemon — juice of ½ a lemon to brighten the sauce.
• Salt — about ¼ teaspoon, adjust to taste.
• Ground white pepper — a small pinch for a subtle appearance (black pepper works too).
• Double cream — 75 g to finish the sauce (use heavy cream or unsweetened cashew cream for dairy-free).

How to make it

Note: exact timings and measurements are in the recipe card below.

1. Roughly chop the parsley and add it to the milk in a medium saucepan.
2. Heat the milk until it is just below boiling, then remove from the heat. Allow the parsley to infuse the milk for at least 30 minutes; longer (up to 4 hours in the fridge) yields a stronger flavour.
3. Measure out 100 ml of the infused milk and whisk the cornflour into it until smooth to form a slurry. Always mix cornflour into cold or room-temperature liquid to avoid lumps.
4. Return the slurry to the remaining parsley-infused milk in the saucepan. Add the Dijon mustard, salt and white pepper, then return to medium heat.
5. Stir constantly and bring the sauce to a gentle boil, making sure to reach into the corners where lumps can form. When it begins to thicken and bubble, lower the heat and continue whisking for about a minute.
6. Remove from the heat, stir in the double cream until combined, add the lemon juice, taste and adjust seasoning, then serve warm.

Tips and troubleshooting

• Rinse parsley thoroughly to remove grit from the leaves.
• Infuse the parsley in the milk for at least 30 minutes; if you have time, up to 4 hours intensifies the herb flavour. If infusing longer than 30 minutes, refrigerate the milk while it steeps.
• Always whisk cornflour into cool or room-temperature liquid. Adding it to hot milk can cause lumps.
• If a skin forms while cooling, press baking parchment onto the surface to prevent it.

Make in advance and storage

You can prepare the parsley-infused milk a day ahead and finish the sauce when needed, or prepare the whole sauce up to two days before serving. Cool with parchment on the surface to prevent a skin, then refrigerate. Reheat gently, adding a splash of milk if the sauce has thickened too much. The sauce can be frozen in an airtight container for up to two months; defrost overnight in the fridge and reheat slowly.

Dairy-free and vegan option

• Replace whole milk with unsweetened plant milk such as cashew, almond or oat milk (cashew milk is particularly silky).
• Replace double cream with unsweetened cashew cream to add richness without dairy. Avoid sweetened or flavoured substitutes.

Using this sauce in a gluten-free fish pie

1. Simmer cubed salmon, smoked haddock and cod in the milk at the start for about 10 minutes, then remove the fish and reserve the milk.
2. Proceed with the parsley sauce method using the reserved milk.
3. Layer the cooked fish in a baking dish, pour over the finished parsley sauce, top with mashed potato and parmesan, then bake until golden.

What to serve with this parsley sauce

• Grilled salmon or firm white fish such as cod, hake or halibut.
• Salmon fishcakes or sautéed shrimp.
• Pork chops, glazed ham or baked ham slices.
• Mashed potatoes on the side make this a comforting, classic meal.

Other gluten-free sauce ideas

• Gluten-free cheese sauce (made with a roux using a gluten-free flour)
• Gluten-free white sauce (béchamel made with cornflour)
• Gluten-free gravies and onion gravy
• Dairy-free peppercorn sauce

This gluten-free creamy parsley sauce is reliable, quick and flavourful — a great recipe to keep in rotation. If you try it, consider leaving a rating or note for others to find this recipe more easily.