Peel and finely slice the onions. Mince the garlic cloves with a pinch of salt until you have a puree.
Pick the thyme leaves.
Heat a saucepan over a medium heat and add the butter. Sweat the onions until soft with the salt, pepper and thyme until nicely caramelised. Stir in the garlic and the flour and cook for a further 2 minutes. Add the cider vinegar and reduce until almost evaporated. Pour in the cider and reduce this by two thirds. Add the veal stock and water and bring to the boil. Once boiling, reduce to a simmer and allow the soup to cook until the onions are completely soft. Check the seasoning and add more salt and pepper if necessary. Add a splash cider vinegar if the soup needs a bit more acidity.
Preheat the oven to 180'C.
Drizzle the olive oil on top of the bread and bake in the oven until golden brown. Rub the garlic clove on the bread and top with Gruyere cheese. Return to the oven for 1 minute to melt the cheese.
Serve with the hot soup.
«The depth of flavour in this soup will come from the sweetness of the onions. Make sure they are nicely caramelised before adding any of the cider or vinegar.»