Serves 6 - 8
2kg large white onions
2 tablespoons olive oil
3 garlic cloves, crushed
1/2 teaspoon sugar
2 tied bunches thyme
300ml dry white wine
2 litres good beef stock, heated
salt & black pepper
2-3 tablespoons Cognac (optional)
16 slices baguette
2 garlic cloves
3oog Gruyere cheese, grated
Peel and thinly slice the onions.
Place the butter and oil in a large heavy based pan over a high heat. Add half the onions and the garlic. Cook for 5-10 minutes until the volume reduces. Add the remaining onions with the sugar. Cook on a high heat stirring occasionally for 10 minutes.
By this time the onions will be wilted and beginning to brown at the edges of the pan.
Turn the heat to the lowest setting. Add the thyme and cook uncovered for an hour, turning the onions about every 20 minutes. Don't move the onions around too much. The full intense flavour comes from the slowly browned caramelised onions. After 1 hour you will be left with a rich brown unctuous heap.
Turn up the heat and pour over the white wine.
To deglaze, use a wooden spoon to stir the sticky residue from the bottom of the pan and mix with the onions.
Add the beef stock and season. Simmer over a low heat for 30-40 minutes with the lid on. Add the Cognac halfway through. This soup would really benefit from resting overnight.
To make the croutons, preheat the oven to 180°C. Halve the garlic cloves and rub them over the baguette slices. Place these on a baking sheet and drizzle with olive oil. Cook in the oven for 15-20 minutes until golden brown and crunchy. Set aside.
To serve, preheat the grill to high. Ladle the soup into warmed ovenproof soup bowls and top each bowl with two croutons. Sprinkle the Gruyere generously over each crouton. Place the bowls under the grill and heat until the cheese is melted and bubbling. Serve immediately.