Poireaux Vinaigrette

Whole leeks poached until silky, pressed dry, and dressed warm in a sharp mustard vinaigrette

Origin: France

From the journey of Leek.

This is on the blackboard of every bistrot in France and it is a straightforward test of whether the kitchen can be bothered. There are three ingredients and no technique to hide behind. Whole leeks are poached until they are entirely tender, pressed to drive out the poaching water, and dressed whilst still warm in a mustard vinaigrette. That is all. What separates a good plate from a bad one is a matter of two or three minutes at the poaching stage and one step that is almost always skipped. The skipped step is the pressing. A poached leek holds an astonishing amount of water between its layers, and if it is not pressed out the dressing is diluted to nothing within a minute of hitting the plate and a pool of grey liquid gathers under it. Wrapping the drained leeks in a cloth and weighting them for twenty minutes solves it entirely. The timing is the other half. A leek that is undercooked squeaks against the teeth and tastes raw at the core; one that is overcooked slumps into separate threads and cannot be cut. The window is narrower than it looks and the test is a knife tip through the thickest part of the white, which should meet no resistance at all. Dressing them warm rather than cold matters too, because a warm leek absorbs the vinaigrette into its layers where a chilled one merely wears it. The French phrase for the vegetable, l'asperge du pauvre, the asparagus of the poor, is usually quoted as a slight and is better read as a claim: treated properly, it deserves the same first-course seriousness.

Ingredients

Leeks

8 whole slender leeks, about 1.2 kg
1 tbsp salt, for the poaching water

Vinaigrette

2 tbsp Dijon mustard
2 tbsp red wine vinegar
1 tsp caster sugar
0.5 tsp salt
0.25 tsp freshly ground black pepper
120 ml neutral oil, or a mix of oil and olive oil

To Finish

1 whole shallot, very finely chopped
2 whole eggs, hard-boiled and finely chopped, optional
2 tbsp flat-leaf parsley or chives, chopped

Method

Trim the roots but leave the base intact, and cut off the coarse dark green tops. Slit each leek lengthways from about 3 cm above the root to the top.
Fan the layers open under cold running water and wash out every trace of soil.
Bring a wide pan of well-salted water to a simmer and lower the leeks in. Poach for 12 to 18 minutes depending on thickness.
Test with the tip of a knife through the thickest part of the white. It should slide in with no resistance whatever.
Lift the leeks out and lay them on a clean tea towel. Fold the cloth over, lay a board on top with a light weight, and leave for twenty minutes.
Meanwhile, whisk the mustard, vinegar, sugar, salt, and pepper together, then beat in the oil in a slow stream until thick and emulsified.
Cut the pressed leeks in half lengthways or leave whole, and arrange on a plate whilst still warm.
Spoon the vinaigrette over generously and scatter with the chopped shallot, the egg if using, and the herbs.
Leave to come to room temperature and serve. Do not refrigerate.

Notes

Slender leeks are far better here than thick ones: they cook evenly and are the right size for a portion. Two per person is a starter. Do not throw away the poaching water. It is a light vegetable stock and is excellent as the base of a soup. The chopped hard-boiled egg makes it poireaux mimosa, which is the fuller version and worth doing. It can be poached and pressed several hours ahead but should be dressed shortly before serving, since the vinegar dulls the green over time. Serve as a first course with good bread, or alongside cold ham or a terrine.

The Gastrographer

Name: Poireaux Vinaigrette
Prep time: 15 min
Cook time: 20 min
Total time: 1 h
Yield: 4
Cuisine: France
Ingredients: 8 whole slender leeks, about 1.2 kg; 1 tbsp salt, for the poaching water; 2 tbsp Dijon mustard; 2 tbsp red wine vinegar; 1 tsp caster sugar; 0.5 tsp salt; 0.25 tsp freshly ground black pepper; 120 ml neutral oil, or a mix of oil and olive oil; 1 whole shallot, very finely chopped; 2 whole eggs, hard-boiled and finely chopped, optional; 2 tbsp flat-leaf parsley or chives, chopped

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Ingredient originTrade or transit route

Became a culinary stapleColonial / trade control