Poached Asparagus with Beurre Blanc

Snap the woody ends from the asparagus and, if using white asparagus, peel each spear from just below the tip down to the base with a vegetable peeler.

Very finely mince the shallots, and cut the cold butter into 1 cm cubes, returning them to the refrigerator until needed.

Combine the water, salt, sugar, and the juice of half the lemon in a wide, shallow saucepan and bring to a rolling boil over high heat.

Add the asparagus in a single layer, reduce the heat to a gentle simmer, and cook for 5–7 minutes for green asparagus or 8–10 minutes for white, until a knife tip meets only slight resistance at the thickest part.

Transfer the asparagus immediately to a wire rack or clean kitchen towel to drain, then tent loosely with foil to keep warm while you build the sauce.

Combine the shallots, white wine, and white wine vinegar in a small, heavy-based saucepan and bring to a boil over medium-high heat; cook until the liquid has reduced to roughly 2–3 tablespoons and the shallots look glazed and jammy.

Remove the pan from the heat and add the cold water; allow the reduction to cool for 30 seconds until it is hot but no longer bubbling fiercely.

Return the pan to the lowest possible heat and begin adding cold butter cubes three or four at a time, whisking constantly and vigorously; each addition should melt into a creamy, opaque emulsion before the next goes in — if the pan feels too hot, lift it off the heat while whisking and return it when the butter cools slightly.

Continue adding butter in small batches, whisking throughout, until all 250 g is incorporated and the sauce is thick, ivory-coloured, and coats the back of a spoon; season with fine sea salt and white pepper, then pass through a fine sieve if a smooth sauce is preferred, pressing the shallots lightly.

Arrange the warm asparagus spears on warmed plates, spoon the beurre blanc generously over the centre, scatter with chives, and finish with a pinch of fleur de sel.