Step 1: Bring a large pot of water to the boil. Add the plum tomatoes to the water and boil for 10-15 seconds. Following this, run the tomatoes under cold water, then peel and quarter them.
Step 2: Peel the ginger (easiest done with a spoon), then finely chop it, along with the garlic cloves and chilli.
Step 3: In a large pan, cook the tomatoes, garlic, ginger and chillies on a low heat until the mixture becomes of pulp-like consistency. Pour the fish sauce, red wine vinegar and Demerara sugar into the mix. Stir well. Season with a little salt and pepper.
Step 4: Don’t wait for the jam to cool - store the jam in a sterilized jar whilst still hot.
Step 5: Scoop a generous spoonful of jam onto your freshly barbecued burger – and enjoy!