Instructions

  1. Melt butter with oil in large saucepan over medium heat.
  2. Add onions, garlic and sugar and cook until lightly-coloured, stirring occasionally, about 6-7 minutes.
  3. Add wine and bring to a boil.
  4. Cook 5 minutes.
  5. Add stock and bring to simmer.
  6. Simmer uncovered for 1 ½ hours.
  7. Season to taste.
  8. (can be prepared 1 day ahead) Preheat broiler.
  9. Ladle soup into 6 ovenproof bowls.
  10. Top with 2 slices of toasted bread each, sprinkle with 1/3 cup Swiss cheese each, sprinkle with ½ tsp Parmesan cheese each.
  11. Broil until cheese melts.
  12. Serve immediately.