Porri Gratinati

Piedmontese leeks poached whole, laid in a dish, and baked under béchamel and Parmesan

Origin: Piedmont, Italy

From the journey of Leek.

Italy grows and eats a good many leeks without making any national fuss about them, and the north is where they matter most. Piedmont and the Alpine foothills cook in butter and cream rather than in olive oil, a fact that surprises people whose idea of Italian food is formed further south, and the gratin belongs squarely to that tradition. Whole leeks are poached until yielding, drained and pressed, laid in a buttered dish, covered with a béchamel, dusted with Parmesan, and baked until the top blisters. It is a contorno, a vegetable dish served alongside a roast or a braise, and in a Piedmontese winter it turns up constantly. The Roman ancestry is not far away. Latin porrum gave Italian porro, Columella wrote about growing the headed leek for its shank, and the emperor Nero's fondness for leeks in oil was famous enough to earn him a nickname. What Italy did not do was build a national dish around it, and the leek stayed a good winter vegetable rather than becoming an emblem the way it did in Wales. The technique to watch is the drying. A poached leek is full of water, and water under a béchamel gives a thin grey pool at the bottom of the dish. The leeks must be pressed after poaching and then, better still, patted dry and given a few minutes in the warm oven before the sauce goes on. A scattering of chopped walnut or a little grated nutmeg in the béchamel are both common Piedmontese additions.

Ingredients

Leeks

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

Béchamel

  • 50 g unsalted butter
  • 50 g plain flour
  • 600 ml whole milk, warmed
  • 1 pinch freshly grated nutmeg
  • 1 tsp salt, or to taste
  • 0.5 tsp freshly ground white pepper

Topping

  • 80 g Parmigiano Reggiano, finely grated
  • 30 g dried breadcrumbs
  • 20 g butter, in small pieces
  • 40 g walnuts, roughly chopped, optional

Method

  1. Trim the leeks, keeping the root ends intact, slit them lengthways, and wash out all the grit under running water.
  2. Poach in well-salted simmering water for 12 to 15 minutes until a knife slides through the white without resistance.
  3. Drain, lay on a clean cloth, fold it over, and press gently with a board for fifteen minutes.
  4. Heat the oven to 200°C. Butter a shallow baking dish and lay the pressed leeks in it in a single layer.
  5. Melt the 50 g of butter in a pan, stir in the flour, and cook the roux gently for two minutes without letting it colour.
  6. Whisk in the warm milk a little at a time, beating smooth after each addition, then simmer for five minutes until it thickly coats a spoon. Season with nutmeg, salt, and white pepper.
  7. Stir half the Parmesan into the sauce, then pour it evenly over the leeks.
  8. Scatter with the remaining Parmesan, the breadcrumbs, the walnuts if using, and dot with the butter.
  9. Bake for 20 to 25 minutes until bubbling and deep golden on top. Rest for five minutes before serving.

Notes

Slender leeks are much better than thick ones: they cook evenly and lie flat in the dish. Thick ones should be halved lengthways. The poaching water makes a good light stock and should not be thrown away. This can be assembled several hours ahead and refrigerated, then baked from cold with an extra ten minutes. A slice of prosciutto cotto wrapped round each leek before the sauce goes on makes it a main course, and is a common Piedmontese variation. Serve alongside a roast, a braise, or a plain grilled meat. It is rich enough that it does not want much else.

The Gastrographer

The Gastrographer

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Became a culinary stapleColonial / trade control
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