Cassoeula Milanese con Verza e Costine

Place the cotenne and the trotter in a large pot of cold, unsalted water. Bring to the boil and blanch for 10 minutes. Drain, rinse under cold running water and pat dry. This step is not negotiable: skipping it leaves the sauce cloudy and greasily dull. The rinds should be firm, pale and odour-neutral when ready.

In a wide, heavy braising pot set over medium heat, melt the butter with the oil. Brown the costine in batches, turning them without crowding, until each surface is a deep mahogany. Set aside. In the same fat, brown the blanched cotenne and trotter. The sound of active sizzling will fade to a quieter crackle when the water has driven off and true browning begins — that quiet crackle is the signal to turn each piece.

Reduce the heat to medium-low. In the residual fat, sweat the onion, carrot and celery together until completely softened and faintly golden, about 12 minutes. The vegetables should yield entirely to pressure and smell sweet and caramelised rather than raw.

Return all browned pork to the pot. Pour in the wine and deglaze, scraping every dark deposit from the base — these fond solids are the backbone of the sauce. Let the wine reduce by half; it should smell of fruit and roasted meat together, with the raw alcohol entirely gone.

Add enough warm stock to come two-thirds of the way up the meat. Bring to a gentle simmer, then reduce the heat to the lowest setting at which the surface moves — a lazy, occasional bubble at the centre. Cover and braise for a minimum of 2 hours. This is where the dish lives or dies: insufficient time means the collagen has not released, the trotter meat will not yield and the sauce will be thin and separate rather than glossy and coating. At the correct moment, a probe or skewer passes through the trotter meat without resistance, and the broth already coats a spoon.

After 1 hour of braising, nestle the musetto whole into the pot without puncturing the casing. Continue braising covered for the remainder of the 2-hour minimum. The sausage is ready when it feels uniformly firm along its length with no soft cold pocket at its core.

With 30 minutes of cooking time remaining, add the verza strips, pressing them down into the liquid. Replace the lid and continue at the same gentle simmer. The cabbage must retain a faint resistance — not raw, but not collapsed. Taste a strip: it should be tender yet hold its shape, and its sweetness should be fully developed.

Remove the lid for the final 15 minutes. Increase the heat to a moderate simmer and allow the sauce to reduce and concentrate. It is ready when it coats the back of a spoon in a glossy, sticky layer and does not run off immediately when the spoon is tilted. Adjust seasoning with restraint.

Remove the musetto, slice it into rounds and return the slices to the pot. Serve directly from the pot over soft polenta or with crusty bread. If serving the following day — the superior option — reheat over low heat and stir in a knob of butter to restore the sauce's gloss and binding consistency.