For the chimichurri: Combine the parsley, olive oil, vinegar, cilantro, crushed red pepper, cumin, salt and garlic in a food processor. Process until well blended. Let stand for at least 1 hour for the flavors to blend.
For the kebabs: Preheat the oven to 400 degrees F. Combine 1/2 cup of the chimichurri with the lamb, cashews, rock salt, 3/4 teaspoon garam masala, the garlic, nutmeg and onions. Knead to combine thoroughly.
Pat the mixture evenly onto the skewers with moist hands and shape into kebabs. Place the kebabs on 2 baking sheets and bake for 8 minutes. Baste with the melted butter, and then continue to cook until completely cooked through, about 8 more minutes. Alternatively, the kebabs can be grilled over medium-high heat until slightly charred on all sides and cooked through, 10 to 12 minutes. Baste the kebabs with the melted butter when they come off the grill.
Sprinkle the kebabs with the remaining chaat masala and the lemon juice and serve hot with the chimichurri on the side. Garnish with chopped cilantro.