French onion soup with cider

Melt butter in a large saucepan over medium heat. Add onions and 1 1/2 teaspoons sea salt and cook, stirring occasionally, for 30 minutes or until onions are deep golden. Add cider and simmer until reduced by half, then add stock and simmer for 10 minutes. Season with pepper.

Meanwhile, place bread on a foil-lined tray and cook both sides under a hot grill until dried but not browned. Spread with mustard and top with cheese, then grill until cheese bubbles and browns. Serve with the hot soup.