Puree the thawed raspberries in a saucepan with a cutting stick. Stir in the glucose and bring to the boil.
Mix the custard powder with the water until lump-free - ideally with a whisk. Add the mixture to the hot raspberries, bring to the boil again and cook for about 1 minute while stirring.
Pour the spread hot into mason jars and close them immediately. Let cool down completely.
I like to eat this spread on bread, but I also find it very tasty mixed with yogurt or quark.