Preheat oven to 375F/190C.
Place the deboned turkey leg between two sheets of plastic wrap and pound lightly with a flat meat tenderizer to an even thickness of about 1 inch. Set aside while you prepare the stuffing.
Place all the pesto ingredients in a large powerful blender and blend until smooth but still chunky. Season and set aside until needed.
Arrange the turkey leg on a flat clean surface and layer the parma ham over the top (if using).
Spread about 3 spoons of pesto on top, leaving out about 1 inch of the edges.
Roll the turkey tightly but gently over itself, making sure the filling doesn't escape. Secure your turkey roulade with meat netting, or use a kitchen string.
Give the roulade a quick seal and sear all sides on a screaming hot cast iron skillet. This will help seal all the meat juices while you cook the turkey in the oven.
Transfer the turkey in the oven and bake until an instant-read meat thermometer inserted in the thickest part registers 165°F, about 45 mins-1 hour.
Remove the turkey from the oven, transfer to a cutting board, cover with aluminum foil, and let rest for 5 mins.
Cut the roulade into thick slices, spoon over the pan juices and serve with your favorite greens and extra pea pesto on top.