• Place the sliced onions in a large saucepan / stockpot and drizzle over the olive oil.
• Toss the onions about so that they are covered in oil.
• Cook the onions over a medium heat for about 30 - 40 minutes stirring every 3 to 5 minutes. You are wanting the onions to brown and caramelize but you do not want them to stick to the bottom of the pan and burn.
• Towards the end of the cooking time you may need to stir them every minute or so to stop them sticking and you can turn the heat down a little.
• If you find that bits start to stick to the bottom of the pan, add a couple of tablespoons of water to the pan and use a wooden spoon to scrape the bits off the bottom.
• Once the onions are nice and caramelized, add the garlic and cook for one or two minutes before adding the white wine vinegar.
• Scrape off anything that has stuck to the bottom of the pan (deglazing). This adds to the flavour.
• Add the flour and stir.
• Add the stock, Worcestershire sauce and sprigs of thyme, if using.
• Stir.
• Bring the soup to a simmer and then cover and turn down the heat so that it gently simmers for about 10 minutes.
• Remove from the heat and carefully fish out the sprigs of thyme.
• Taste and add salt and pepper if required.

For the cheesy croutons (additional SmartPoints*)

• Slice 5 x 1 inch pieces from a crusty baguette.
• Place the slices of bread on a baking sheet place under the grill/broiler until they start to toast. Turn and toast the other side.
• Remove the slices of bread from under the grill / broiler.
• Place one piece of the grilled bread into each of bowls of soup.
• Carefully pile about 10g of cheese on the top of each slice of bread and place the bowl of soup under the grill / broiler until the cheese starts to melt and bubble.