-
1
Place the drained borlotti in a large pot with the Parmigiano rind and cover generously with cold water. Bring to a simmer without salt — salt at this stage would tighten the skins and leave the centres chalky rather than uniformly creamy — and cook until the beans are just tender, 60–80 minutes. Reserve all cooking liquid and discard the rind; the broth must be opaque and legume-scented, because this liquid carries as much flavour into the finished dish as the beans themselves.
-
2
Bring a separate pot of salted water to the boil. Add the stripped cavolo nero leaves and blanch for 3–4 minutes until pliable and dark, so that the bitterness softens but the leaves retain enough body to hold texture through tomorrow's long simmer. Drain, squeeze firmly to expel as much water as possible — excess water would thin the broth you have worked to concentrate — and roughly chop.
-
3
In a wide, heavy pot, warm the 60 ml of olive oil over a medium flame. Add the onion, celery, carrot, and garlic and cook gently, stirring, until the vegetables are soft and translucent, 10–12 minutes, so the sweetness fully releases into the fat that will carry it through the whole soup. Add the rosemary sprigs and continue until the raw edge has gone from the onion and the mixture is fragrant without colouring.
-
4
Pour the cooked borlotti and all their reserved broth into the soffritto pot and bring to a steady simmer, then add the drained soaked farro so that it cooks entirely in the bean broth, absorbing the legume flavour throughout rather than swelling in plain water. Add the blanched cavolo nero, then cook, stirring occasionally and adding water only in small measures if the preparation seizes, until the farro is fully cooked and the mixture is thick enough to hold a channel when a spoon is drawn across the base of the pot, approximately 40–50 minutes. This is where the dish lives or dies: keep the simmer gentle and resist diluting with excess water, or the farro will bloat without flavour and the finished crust will not hold.
-
5
Remove the rosemary sprigs and adjust salt. Transfer the preparation to a container, allow it to cool to room temperature, then refrigerate overnight so the farro continues to absorb the residual liquid and the mixture stiffens into a mass that will hold its shape and form a proper crust when fried. The texture in the morning should be firm enough to slice.
-
6
Set a cast-iron pan over a medium flame, add a film of the 45 ml of olive oil, and allow it to heat until it shimmers. Spoon the cold farro-bean preparation into the pan and press it flat with the back of a spoon — starting from cold ensures the interior warms through gradually while the base has time to build a deep crust rather than scorching before the centre is hot. Cook without stirring or disturbing the base for 4–5 minutes; the crust is ready when the underside is audibly crackling and releases cleanly from the pan — lift one edge to check for a deep golden-brown colour before proceeding.
-
7
Scoop portions directly from the pan so each plate carries both the crusted base and the warm grain interior; the preparation should hold its shape on the plate, not pour. Finish each portion with a thread of raw Garfagnana extra-virgin olive oil and a grating of Pecorino Toscano DOP.