Preheat the oven to 180°C. Line a large baking sheet with baking paper.
1 Heat the oil and butter in a large pan and lightly fry the onions for 15-20 minutes or until it starts changing colour.
2 Add the garlic, bay leaves, thyme and brown sugar and fry for another 5-10 minutes until golden. Transfer to a mixing bowl and allow to cool down slightly.