For maltagliati di pane, combine flour, bread crumbs and 1 tsp fine salt in a large bowl. Make a well in the centre, add eggs and parsley, stir to combine, then turn onto a lightly floured surface and knead until smooth (4-5 minutes). Wrap in plastic wrap and refrigerate to rest (1 hour). Roll out on a lightly floured surface with a rolling pin to 3mm thick cover with a damp tea towel and set aside to rest (5-10 minutes). Cut into 2.5cm-wide strips with a fluted pastry wheel, then cut into rough diamonds. Lay on a tray lightly dusted with semolina and set aside to dry (3 hours)
Preheat oven to 150C. Heat oil in a large casserole over medium-high heat, add lamb season to taste and turn occasionally until golden (3-5 minutes). Remove lamb and set aside. Add pancetta, onion, celery, carrot and garlic to casserole, stir occasionally until golden (7-10 minutes), deglaze casserole with wine, add tomatoes, stock and rosemary and bring to the simmer. Add lamb, cover and braise in oven until lamb is very tender (2 1/2 - 2 3/4 hours). Remove lamb with a slotted spoon and set aside. Simmer braising liquid over medium heat until slightly thickened (8-10 minutes). Coarsely shred lamb (discard fat and sinew), return to sauce with peas, simmer until just tender (1 minute), add vinegar and keep warm.
Meanwhile, cook pasta in a large saucepan of boiling salted water until al dente (3-4 minutes), drain (reserve 30ml pasta water), return to pan with pasta water and lamb and toss to combine. Serve hot scattered with pecorino pepato and parmesan.