One idea could be exploring the backstory of the Lamb before it became the cult leader. Maybe it was a simple, innocent creature that got caught in a dark magic experiment. Another could be a story about the relationships between the cult members, like rivalries or secret friendships.
A sandwich novel is a form of literary work. It often consists of different narrative layers. The 'filling' part is the core of the story, around which there are other elements that add depth and complexity. It's like a sandwich where the main ingredient is the focus, but the bread and other toppings enhance the overall taste. In a sandwich novel, the outer 'layers' might introduce characters or situations that lead into the main story and also tie up loose ends after the main plot has been told.
The lamb in the story has multiple significances. Firstly, it is a literal object, which is used as the murder weapon. Secondly, it represents Mary's innocence in a way at the start. Just as a lamb is often seen as a symbol of meekness and innocence, Mary was like that before her husband's news. But then it becomes a tool for her to commit a crime, which is a kind of ironic twist on the traditional symbol of the lamb.
The sandwich is said to have originated from John Montagu, the 4th Earl of Sandwich. He was a gambler who didn't want to leave the gaming table to have a meal. So, he asked his servants to put meat between two slices of bread. This convenient way of eating soon became popular and was named after him.
It might also be a symbol of power or control. If a character has control over the leg of lamb, whether it's in terms of cooking it, serving it, or using it in some other way, it could show their position in the family or social hierarchy within the story. For instance, if a mother is in charge of cooking the leg of lamb, it could show her role as the provider and caregiver in the family. Moreover, if the leg of lamb is stolen or fought over, it would further emphasize its value as a symbol of power.