Preheat your oven to 200C/400F
Place each chicken between 2 sheets of plastic wrap and then beat with a meat mallet or the bottom of your cast iron skillet. Flatten the breast evenly until about 5mm thick.
Melt the butter in a non-stick pan and gently sauté the onion until it softens. Add the garlic and cook briefly season with salt and white pepper and set aside to cool.
In the bowl of a small food processor, pulse the sultanas, sage, and parsley until it forms a paste.
Mix this with the other stuffing ingredients until well combined and then roughly divide into 4 portions.
Place a flattened chicken breast, smooth side down on a board, lightly season the surface, and then spread 1/4 of the stuffing evenly over. Roll up and tuck in any loose edges or stuffing that may have fallen out. Wrap 1 – 2 slices of prosciutto around each breast. Place the stuffed breast with seam side down and tie three pieces of string to secure the roll. Tuck a sage leaf under the string for decoration (and added flavour).
Brush the chicken rolls with olive oil and roast in the oven for 20 minutes until golden brown and cooked through.
Served with green beans or anything you fancy