Preheat the oven to 425 degrees F.

Warm the olive oil in a large skillet over medium heat. Add the onion, garlic and thyme and sauté ingredients until softened and lightly browned, about 2-3 minutes.  Add the tomatoes and continue to cook, stirring occasionally for an additional 5-6 minutes or until the tomatoes are cooked through, but not broken apart. Remove from the heat and set aside.

Coarsely chop 1 cup of the pistachios; set aside.

Place the lamb in a large bowl. Mix in the salt, pepper, cumin, egg, breadcrumbs and chopped pistachios and blend together until ingredients are evenly incorporated. Form the meat into 2-ounce balls and set them on a sheet pan.  Drizzle the 2 tablespoons of olive oil over the meatballs.  Place meatballs in the preheated oven for 10-11 minutes or until gently browned.

Using a food processor, blend the remaining 1/3 cup pistachios until nearly powdered. Transfer pistachio powder into a small bowl and combine with the Parmesan cheese.

Preheat the broiler. 

Transfer the tomato mixture into a large oven-proof gratin dish.  Nestle the meatballs into the tomato sauce. Sprinkle the pistachio-Parmesan mixture all over the top and drizzle with the extra virgin olive oil. Place gratin dish under the broiler for 3-4 minutes, or until the cheese is melted and the ingredients are warmed through. Serve immediately.