Homemade apple & rhubarb ketchup

Giacomo Gianniotti’s recipe, good for 250 ml: warm 200 ml of apple juice in a saucepan. Add 50 g of cut rhubarb, 15 g of ginger, 30 ml of cinnamon syrup, and 20 ml of apple cider. Bring to a boil while stirring. Cool and filter into a separate container. Store in the refrigerator.