How do I turn mayonnaise into tartare, marie rose and other sauces?

Once you have mayonnaise — homemade or a good bought one — you have the base for most of the cold sauces in a British kitchen. The pattern is always the same: mayonnaise for body and fat, something sharp to stop it being cloying, and something aromatic for identity. Knowing the pattern means you can build them without a recipe and adjust them to what is in the fridge.

Step by step

1. Start with roughly 150g of mayonnaise for four people.That is about six generous tablespoons. Every quantity below assumes that as the base. Homemade is better but a good thick bought mayonnaise is an entirely respectable starting point.
2. Tartare: capers, gherkins, shallot, parsley, lemon.A tablespoon each of finely chopped capers and cornichons, half a small shallot finely diced, a tablespoon of chopped parsley, and lemon juice to taste. Chop everything small — the texture should be studded, not chunky. Rest it ten minutes before serving.
3. Marie rose: ketchup, Worcestershire, lemon, a drop of Tabasco.Two tablespoons of tomato ketchup to six of mayonnaise, a teaspoon of Worcestershire sauce, a good squeeze of lemon, a couple of drops of Tabasco and a pinch of cayenne. The lemon is what stops it tasting like sweet pink mayonnaise.
4. Burger sauce: ketchup, mustard, gherkin, a pinch of sugar and paprika.Three tablespoons of ketchup, a tablespoon of American mustard, two tablespoons of very finely chopped gherkin plus a splash of the pickle liquid, a teaspoon of sugar, half a teaspoon of smoked paprika, a pinch of onion powder.
5. Remoulade: mustard, capers, anchovy, tarragon.A tablespoon of Dijon, a tablespoon of chopped capers, two anchovy fillets mashed to a paste, chopped tarragon and parsley. Sharper and more savoury than tartare. The classic partner for a celeriac remoulade or cold meat.
6. Herb mayonnaise, tonnato and rouille for the less obvious ones.Herb: a large handful of soft herbs blitzed in, plus lemon. Tonnato: mayonnaise blended with a small tin of tuna, anchovy, capers and lemon until pourable — for cold veal, chicken or roast vegetables. Rouille: mayonnaise with garlic paste, saffron soaked in a spoon of hot water, and cayenne, for fish soup.
7. Taste it cold, and always add acid last.Mayonnaise-based sauces almost always want more lemon or vinegar than you expect, because fat blunts everything. Add it a teaspoon at a time at the end and taste after each.

Tips

• Chop the solids much finer than looks necessary. A tartare with chunks of gherkin reads as mayonnaise with things in it rather than as a sauce.
• Salt the shallot with the lemon juice for five minutes before it goes in. It takes the raw edge off and gives the sauce a cleaner flavour.
• Ranch is buttermilk-loosened mayonnaise: mayonnaise, buttermilk or soured cream, dried dill, chives, garlic and onion powder, lots of black pepper.
• These keep as long as the mayonnaise underneath them does — three days for homemade, the jar's date for bought. The ones containing fresh herbs go dull after a day.
• A tablespoon of the pickle liquid is worth more than a tablespoon more gherkin. It carries the acidity through the whole sauce.

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