In a large saucepan, combine the stock, red wine, 9 tablespoons of the roasted garlic, the shallots and 3/4 cup of the chopped parsley. Bring to a simmer over medium heat and cook until reduced to coat the back of a spoon, about 20 minutes.
Transfer mixture to a blender and puree until smooth. Strain through a fine sieve into another saucepan, then adjust the salt and pepper. Stir in the remaining parsley, then reduce heat to low.
In a small bowl, combine the remaining garlic, the pistachios, sunflower seeds and 6 tablespoons of the Red Wine sauce. Mix well and set aside. Rub the surface of the steaks with the olive or corn oil.
Grill the steaks until well seared on the surface - both sides. Place in a baking dish. Bake at 300°F for about 5-7 minutes for medium-rare, depending on the thickness.
Brush the tops of the steaks with a small amount of Red Wine sauce, and then press the steaks, topside down, into the pistachio mixture, coating the surface well. Position the steaks on serving platter, spoon the remaining sauce around them, garnish with parsley sprigs and serve.
Note: the nut garnish/topping can be added to the sauce, just before adjusting the salt and pepper.