-
1
Place the borlotti beans in a pot of cold, unsalted water and bring to a gentle simmer. Cook until completely tender, 60–90 minutes depending on age of the beans. Remove from heat and reserve the beans in their cooking liquid. The beans are ready when they yield without resistance at the centre.
-
2
In a large, heavy pot, render the pancetta lardellata over medium heat until the fat runs and the pieces colour lightly. Add the onion and sweat, stirring occasionally, until it is soft and translucent but has taken no colour. Add the Parmigiano rind. The soffritto is ready when the onion is entirely limp and its raw smell has left the pot.
-
3
Add the potato, carrot, and celery to the pot. Cover generously with cold water, season with salt, and bring to a steady simmer. Cook for 20 minutes, or until the root vegetables have begun to soften but retain their shape when pressed with a spoon.
-
4
Add the borlotti beans together with all of their cooking liquid. Stir to combine, adjust the water level so the soup remains loose, and return to a simmer.
-
5
Add the rice — Arborio or Vialone Nano; pasta is not used in the Milanese recipe. Set a timer for 18–20 minutes. After 10 minutes, add the zucchini and peas. The rice is ready when it is cooked through but still holds a distinct bite at its core and the soup has thickened to a dense, spoonable consistency.
-
6
While the rice cooks, pound the lardo, garlic, and rosemary leaves together in a mortar until the mixture forms a smooth, cohesive paste. This is the pestata di lardo — the Lombard ancestor of Ligurian pesto. This is where the dish lives or dies: the pestata must be stirred into the soup off heat, immediately before serving, never simmered or cooked into the pot. The aromatic compounds are volatile; heat destroys them. Remove the pot from the flame, stir in the pestata completely, and serve at once. The soup should smell of lard, rosemary, and garlic the moment the paste meets the hot liquid.