Blueberry and blackcurrant jam

Method

A day in advance 1 Wash 250g of blueberries and all the blackcurrants, and mix them with sugar. 2 Scrape out the seeds and add ½ of a vanilla pod to the mixture. 3 Let the mixture sit overnight. Day of 4 Combine the cornstarch with a little water until you make a smooth paste. 5 Bring the berry and sugar mix to a boil, reduce the heat, and let the mixture simmer. 6 Add the cornstarch mix, and heat until the jam has thickened. 7 Remove the pot from the heat and let the jam cool. 8 Once cool, add the remaining 250g of fresh, clean blueberries and the grapefruit juice. 9 Serve cold with pancakes or porridge.