Slice the turkey breast with a butterfly cut so that you can open it lengthwise.
Place the unfolded breast between two sheets of baking paper and pound flat with a meat mallet or rolling pin. Ideally, it should be about 20 x 30 cm in size.
For the filling, peel the sausage meat from the salsiccia and mix in a bowl with the breadcrumbs, finely chopped needles from a sprig of rosemary, the fennel seeds, 2 tablespoons of olive oil, salt and pepper.
Preheat the oven to 180 °C.
On a sheet of baking paper, lay out an area the size of the turkey breast with slices of prosciutto. Make sure that the slices overlap slightly.
Now place the breast on the prosciutto and spread the filling in the middle lengthwise from the far left to the far right. Then roll the whole thing up like a strudel. Place the remaining sprigs of rosemary on the roll and tie everything up tightly with kitchen string at regular intervals.
Place the roll in a roasting tin and bake at 180°C for 35-40 minutes. Then remove and leave to rest for 5 minutes. Finally, cut into slices and arrange on a platter.