Delia Smith All In One White Sauce Recipe

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This is Delia Smith’s brilliantly simple all-in-one white sauce, made by putting everything in the pan at once and whisking until silky smooth. The texture is creamy and velvety, with a clean, buttery flavour that takes well to cheese, mustard, herbs, or a pinch of nutmeg. It’s an easy, beginner-friendly method with no separate roux step, and it’s ready in about 15 minutes from start to finish. Use it for lasagne, macaroni cheese, fish pie topping, cauliflower cheese, or any comforting bake that needs a dependable white sauce.

Delia Smith All In One White Sauce Recipe

Ingredients

For the all-in-one white sauce

50g unsalted butter (about 3 1/2 tbsp), cut into small cubes
50g plain flour (about 6 tbsp)
600ml whole milk (2 1/2 cups)
1/4 tsp fine salt, plus more to taste
Freshly ground black pepper (or white pepper), to taste

Optional flavour add-ins

Pinch of freshly grated nutmeg
1 bay leaf (remove before using)
1 tsp Dijon mustard (great for fish pie or cauliflower cheese)
75–100g mature Cheddar, grated (to turn it into a quick cheese sauce)

How to Make Delia Smith All In One White Sauce Recipe

Prepare the oven: If you’re using this sauce in a bake (lasagne, cauliflower cheese, fish pie), preheat the oven to 200°C or 180°C fan and set a shelf in the middle. If you’re using it on the hob only, you can skip this step.
Mix everything in one pan: Set a medium saucepan over medium heat (keep it off the heat for the first 30 seconds if you prefer). Add the butter, flour, milk, salt, pepper, and nutmeg (plus a bay leaf if using).
Whisk until smooth: Whisk continuously as the butter melts. At first it can look a little messy, but keep going and it will quickly turn into a smooth, creamy liquid.
Cook (the thickening step): Keep whisking until the sauce comes to a gentle boil and noticeably thickens. Once it bubbles, turn the heat down and simmer for 2 to 3 minutes, whisking often, so the flour cooks out and the sauce becomes glossy.
Bake (optional): If you’re finishing a dish in the oven, pour or spread the hot sauce over your prepared filling (pasta, fish pie mix, vegetables), then bake until bubbling and lightly golden on top, typically 15 to 30 minutes depending on the recipe.
Cool (if making ahead): To prevent a skin, press a piece of baking parchment or cling film directly onto the surface of the sauce. Cool to room temperature, then refrigerate.
Assemble and use: Taste and adjust seasoning. Remove the bay leaf if used. Stir in any extras (mustard, cheese, herbs), then use straight away in your dish or reheat gently with a splash of milk until smooth.

Tips

Why is my white sauce lumpy?

Lumps usually happen when the heat is too high too soon or the sauce isn’t whisked consistently through the first few minutes. Start on medium heat and whisk constantly until it reaches a boil. If you do get lumps, take the pan off the heat and whisk vigorously, or blend briefly with a hand blender.

How do I make it thicker or thinner?

For a thicker sauce, simmer 1 to 2 minutes longer after it reaches a gentle boil. For a thinner pouring sauce, whisk in extra milk a splash at a time until it’s the consistency you want.

How do I stop a skin forming on top?

Press baking parchment or cling film directly onto the surface while it cools. This blocks air contact, which is what forms the skin.

How can I add more flavour without overpowering it?

A pinch of nutmeg adds warmth without tasting “spiced.” For savoury bakes, try 1 teaspoon Dijon mustard or a small handful of grated mature Cheddar. Add extras after the sauce has thickened so you can taste as you go.

Serving Suggestions

Layer into lasagne or cannelloni.
Pour over steamed cauliflower or leeks, top with cheese, and bake until bubbling.
Stir into cooked pasta with grated Cheddar for a quick macaroni-style supper.
Spoon over poached fish or chicken and finish under the grill with breadcrumbs.

Storage

Room temperature

Cool the sauce quickly and don’t leave it out for more than 2 hours. Because it’s milk-based, it’s safest to refrigerate as soon as it has cooled.

Refrigerator

Store in an airtight container for up to 3 days. For best texture, press parchment or cling film onto the surface before sealing. Reheat gently on the hob, whisking often, with a splash of milk to loosen.

Freezing

You can freeze white sauce for up to 2 months, though it may separate slightly when thawed. Defrost overnight in the fridge, then reheat slowly, whisking well (a hand blender helps bring it back to silky smooth).

Nutrition

Calories: 120 kcal
Carbohydrates: 9 g
Protein: 4 g
Fat: 8 g
Saturated fat: 5 g
Sodium: 180 mg

Nutrition values are estimates and will vary depending on ingredients used and portion size.

FAQs

Can I make Delia Smith all-in-one white sauce with semi-skimmed milk?

Yes. Whole milk gives the creamiest texture, but semi-skimmed works well. The sauce may be slightly less rich, so season carefully and consider adding a small knob of butter at the end if you want more richness.

How do I turn this into a cheese sauce?

Once the sauce has thickened and you’ve taken it off the heat, stir in 75–100g grated mature Cheddar (or Gruyère) until melted. Taste, then add more pepper or a little mustard if you like.

Why does my white sauce taste floury?

It needs a short simmer after it reaches the boil. Let it bubble gently for 2–3 minutes, whisking often, which cooks the flour properly and gives a smoother flavour.

Can I make this white sauce ahead of time for lasagne?

Absolutely. Make the sauce, cool it with parchment or cling film pressed directly on the surface, then refrigerate for up to 3 days. Reheat gently with a splash of milk, whisking until smooth before assembling your lasagne.

What’s the best pan and whisk to use to avoid lumps?

A medium, heavy-bottomed saucepan helps prevent scorching, and a balloon whisk makes it easier to reach the edges and base. Keep whisking as it heats, especially in the first few minutes, and you’ll get a smooth sauce.