Question: Betty Williams created the signature dish that consists of what principal ingredients?

Context paragraphs:
Betty Williams (Coronation Street): Elizabeth "Betty" Williams (also Preston and Turpin) is a fictional character from the ITV soap opera, "Coronation Street", portrayed by former music hall star Betty Driver.  Driver was cast as Betty in 1969, after first auditioning for the role of Hilda Ogden, which was given to Jean Alexander.  The character arrived in "Coronation Street" to help her sister Maggie Cooke run the corner shop, and has since had a number of storylines which have seen her become twice widowed, and mother to an illegitimate son.  Working as a barmaid in the soap's Rovers Return Inn, Betty created a signature dish, known as Betty's hotpot.

Chicken Divan: Chicken Divan is a chicken casserole usually served with broccoli, almonds, and Mornay sauce.  It was named after the place of its invention, the Divan Parisienne Restaurant in the New York City Chatham Hotel where it was served as the signature dish in the early twentieth century.  Its creator, a chef named Lagasi, created it as part of a contest, winning a small amount of money and creating the hotel's signature dish.  In French, the word "divan" refers to a meeting place or great hall, and thus the name was chosen to imply a kind of continental elegance.

Signature dish: A signature dish is a recipe that identifies an individual chef.  Ideally it should be unique and allow an informed gastronome to name the chef in a blind tasting.  It can be thought of as the culinary equivalent of an artist finding their own style, or an author finding their own voice.  In practice a chef's signature dish often changes with time or they may claim several signature dishes.

Nobu Matsuhisa: Nobuyuki "Nobu" Matsuhisa (松久 信幸 "Matsuhisa Nobuyuki"; born March 10, 1949) is a Japanese celebrity chef and restaurateur known for his fusion cuisine blending traditional Japanese dishes with Peruvian ingredients.  His signature dish is black cod in miso.

Nobel Women's Initiative: The Nobel Women's Initiative was created in 2006 by six female winners of the Nobel peace prize to support women's groups around the world in campaigning for justice, peace and equality.  The six founders are Shirin Ebadi, Wangari Maathai, Rigoberta Menchú, Jody Williams, Mairead Maguire, and Betty Williams.  The only other living female Nobel peace prize winner, Aung San Suu Kyi, was under house arrest at the time of the initiative's formation.  She became an honorary member on her release in 2010.  The initiative's first conference, in 2007, focused on women, conflict and security in the Middle East.

Tetsuya's: Tetsuya's is a restaurant in Sydney, Australia, owned and operated by world renowned chef Tetsuya Wakuda.  Tetsuya's cuisine is based on Australian, Japanese cuisine and classic French cuisine, and makes use of Australian ingredients.  The restaurant is most famous for its signature dish, the Confit of Tasmanian Ocean Trout, commonly referred to as "the world's most photographed dish", which remains on the menu twenty years after its inception.  Tetsuya's, along with the iconic French establishment Claude's, is credited with bringing a new style of fine-dining cuisine to Sydney.

Lancashire hotpot: Lancashire hotpot is a stew originating from Lancashire in the North West of England.  It consists of lamb or mutton and onion, topped with sliced potatoes and baked in a heavy pot on a low heat.

Nut roast: A nut roast or roasted nut loaf is a rich and savoury vegetarian dish consisting of nuts, grains, vegetable oils, broth or butter, and seasonings formed into a firm loaf shape or long casserole dish before roasting and often eaten as an alternative to a traditional British style roast dinner.  It is popular with vegetarians at Christmas, as well as part of a traditional Sunday roast.  Nut roasts are also made by Canadian and American vegetarians and vegans as the main dish for Thanksgiving or other harvest festival meals.  The dish is popular across the world, gaining particular fame in Essex, UK where local celebrity chef David Price produces it as his signature dish.

Picarones: Picarones (or Picaron "singular") is a Peruvian dessert that originated in Lima during the viceroyalty.  It is somewhat similar to buñuelos, a type of doughnut brought to the colonies by Spanish conquistadors.  Its principal ingredients are squash and sweet potato.  It is served in a doughnut form and covered with syrup, made from chancaca (solidified molasses).  It is traditional to serve picarones when people prepare anticuchos, another traditional Peruvian dish.

Betty Driver: Elizabeth Mary "Betty" Driver, MBE (20 May 1920 – 15 October 2011) was a British actress and singer, best known for her role as Betty Williams (previously Betty Turpin) on the British soap opera, "Coronation Street" from 1969 to 2011, appearing in more than 2,800 episodes.  She had previously appeared as Mrs Edgley in "Coronation Street" spin-off "Pardon the Expression" (1965–1966) opposite Arthur Lowe.  Her early career focussed on her as a singer, appearing in musical films such as "Boots!  Boots! " in 1934, opposite George Formby and "Penny Paradise" in 1938, directed by Carol Reed.  She was made an MBE in the 2000 New Year Honours.

Supporting paragraphs: Betty Williams (Coronation Street) Lancashire hotpot
Answer: lamb or mutton and onion