Preheat a grill pan over medium high heat.
Place parsley and garlic in food processor and chop.
Heat a large, heavy skillet over high heat.
Cut chorizo on an angle in 1/2-inch slices. Grill 2 minutes on each side. Transfer to a serving dish.
To the hot skillet, add about 2 tablespoons extra-virgin olive oil, 2 turns of the pan. Add meat and sear the pieces on all sides to caramelize it evenly. Add half of the garlic and parsley mixture to the pan. Turn to coat the meat. Season meat with salt and pepper. Add 1/2 cup sherry and turn the meat in the wine as it deglazes the pan. Transfer to a serving dish and cover with loose foil to keep warm. Return pan to heat.
Repeat the same process with the mushrooms: add extra-virgin olive oil to the pan, 2 tablespoons or 2 turns of the pan. Add mushrooms, cook 3 or 4 minutes to char edges and soften, add parsley and garlic, then salt and pepper, then sherry. Reduce sherry while scraping up pan drippings and remove to serving dish.