Preheat oven to 200C. Combine beans, radicchio, garlic and anchovy fillets in a roasting pan, drizzle with olive oil and roast until starting to caramelise, adding rosemary in last 4 minutes of cooking (15-17 minutes). Drizzle with balsamic and season to taste.
Meanwhile, cook pasta in boiling water until al dente (6-10 minutes). Drain well, toss with bean mixture and Gorgonzola and serve drizzled with extra-virgin olive oil and scattered with walnuts.