1. Melt butter in a large skillet over medium heat. Add onions and cook, stirring often, until soft, 5-7 minutes. Transfer onions and any accumulated juices to a large mixing bowl, then add bread crumbs, parsley, fresh rosemary, summer savory, sage, chicken stock, and sherry, and season to taste with salt and pepper. Toss to mix well, then add shrimp and mix well again. Set stuffing aside.