In an oven proof saucepan, heat the oil and sauté the onions for 10 minutes or until golden.
Add the garlic and the sugar.
Add the beef stock and stir well.
Bring to the boil, then turn the heat to low and simmer covered for 20-30 minutes. Season to taste.
Lightly grill (or toast) the slices of baguette, top with cheese.
Place the cheese topped baguettes on the soup and place under the grill for 5 minutes, so that the cheese melts.
Sprinkle with parsley and serve.
