Bring the pork to room temperature an hour before cooking.
Cut cross cuts into fat.
A sharp knife is needed to handle the meat. A fish filleting knife is good at this point.
Cut a longitudinal incision halfway through the meat on the pork tenderloin. Turn the knife 90 degrees to the left and cut the incision almost to the edge. Make a similar incision on the right side of the meat. This will give the fillet a "T" shaped cut and can be opened up like a leaflet to make the widest possible cut.
Make one centimetre deep slits lengthwise on the inside. This will give the meat some flexibility. Turn the incisions horizontally towards you. Salt and pepper the meat and rub it into the incisions.
Finely chop the stuffing ingredients in a bowl. Break the almonds into slightly smaller pieces. Add a couple tablespoons of oil from the can of tomatoes. Mix well and rub the filling into the meat and slices. Place the prosciutto strips evenly over the meat.
Wrap the meat in a tight roll. Tie the pork roll with a roaster's cord. Put rosemary sprigs between the line and the meat.
Place the pork roll in the roasting tin, fat side up. Place the meat in the oven at 225C / 10 minutes.
After 10 Mins reduce the oven temperature to 150C. Baking time about an hour per kilo.
If you use a roasting thermometer, the internal temperature of 75C is sufficient for the pork. When the liquid starts to escape, baste the pork roll with it every 20 minutes.