- Melt butter in a large, wide heavy-based saucepan over medium heat, add onions, cover and cook, stirring occasionally until onions are soft. Remove the lid and cook for 1 hour until the onions begin to caramelise.
- Add stock, ½ a cup at a time, and simmer for 5 minutes or until stock has almost evaporated. Repeat three times more until 2 cups of stock has been added.
- Using kitchen twine, tie herbs together, add to onions with remaining stock and season to taste with sea salt and freshly ground black pepper. Bring to a boil, reduce heat and simmer, scraping the base to remove any caramelised bits, for 40 minutes or until thick. Makes 6 cups.
- Preheat the oven to 200C. Ladle soup into 1½ capacity oven-proof bowls and transfer to an oven tray. Scatter with half the cheese, top each with two toasted baguette slices and scatter with remaining cheese. Place in the oven and cook for 5 minutes or until the cheese melts. Serve immediately.
Source: Gourmet Traveller