1. Make sauce: In a blender, puree pistachios with 1/4 cup parsley and 1/4 cup water until smooth (add a splash more water if necessary); season well with salt and pepper. Set aside.

2. Heat a large skillet over medium-high. Season lamb with salt and pepper, and place in skillet. Cook until medium-rare, 4 to 6 minutes per side. Transfer to a plate, and cover loosely with aluminum foil. Reserve skillet (and any fat left in it).

3. Add tomatoes, artichokes, and 1/4 cup water to skillet; season with salt and pepper. Cook over medium-high, stirring frequently, until tomatoes begin to soften, 6 to 8 minutes. Mix in remaining 1/2 cup parsley. Serve lamb with vegetable saute and pistachio sauce.