Briefly soak the anchovy. Cook the spaghetti in plenty of salted water until al dente.
In the meantime, chop the capers and olives a little. Strip the rosemary needles from the branch. Chop the anchovy, rosemary, garlic and parsley.
Briefly toast the breadcrumbs in a pan without fat and remove. In the same pan, sauté the garlic, anchovy and rosemary in 3 tablespoons of olive oil. Add the olives and capers and continue cooking until the spaghetti is ready. Add a few tablespoons of the cooking water to the sauce.
Strain the spaghetti and mix thoroughly with the sauce. Sprinkle breadcrumbs and parsley on top and mix again roughly. Serve with freshly grated Parmesan cheese.