Ingredients
125 ml pineapple juice 
40ml rice vinegar 
1 tbsp soy sauce 
1½ tbsp ketchup 
85g soft light brown sugar 
2½ tsp cornflour 
1 tbsp water 

Method
Put the pineapple juice, vinegar, soy sauce, ketchup and sugar into a saucepan and bring to the boil. 

Meanwhile mix the cornflour with the water carefully until completely mixed.  If it is too thick add a drop more water. 

Once the mixture has boiled add the cornflour and stir constantly until thickened.  This should take only a minute or so. 

You can either use now or cool completely, put in the fridge and just reheat when you want it.