1. Preheat the oven to 390F/Gas Mark 6.
  2. Place a heavy bottomed saucepan over a medium heat and add Kerrygold Unsalted Butter. Once the butter has melted, turn down the heat to low and stir in the onions. Cover and leave to cook for 10 minutes, until soft.
  3. Next stir in the brown sugar and garlic and let the onions brown uncovered and slightly caramelize, stirring every few minutes until they become a deep golden colour. Stir in a teaspoon of the dried oregano, fresh thyme or rosemary. Season with sea salt and freshly ground black pepper.
  4. Pour in the beef broth and allow to cook for a further 30 minutes.
  5. To make the Kerrygold Dubliner® Cheese croutons, arrange the cubed sourdough on a baking sheet. Mix together the grated Kerrygold Dubliner® Cheese and melted Kerrygold Unsalted Butter in a bowl then dip the croutons in the melted butter and cheese mixture. Place in the preheated oven for 10 minutes.
  6. Serve the onion soup in heated bowls and place the Dubliner® croutons on top.