Layer one. Ragù alla Bolognese. Beef and pork softened in soffritto, the milk poured in first to round the acidity, then dry white wine, then passata. Three hours on the lowest flame until the meat melts into the sauce and the colour turns from red to a deep, slow brown.

Layer two. Béchamel. Butter and flour cooked to a pale blond roux, warm milk whisked in steadily until the sauce coats a spoon. Salt, white pepper, a single grate of nutmeg. Loose enough to pour, thick enough to hold.

Layer three. Sfoglia. Fresh egg pasta rolled paper thin on a wooden board. The Bolognese version uses spinach in the dough for the verde, but pale gold sheets are equally classic. Dried sheets work but parboil for two minutes first.

Layer four. The bake. Six to eight layers in a buttered dish, ragù and béchamel alternating with sheets, Parmigiano on every level. Forty minutes at 180°C until the top blisters and the edges crisp into dark amber.

Layer five. The rest. Ten minutes on the counter before the knife touches the dish. Skip this and the layers slide into soup on the plate. Wait, and the cross section sets into clean stripes of pasta, ragù, and béchamel.