Clean and sort the blueberries. Fillet the grapefruit by halving it and cutting it around the edge of the fruit with a sharp knife and then again between the dividers. Now you can easily pull out the fillet pieces. Use a simple juicer to squeeze the remaining juice out of the hollowed out grapefruit halves.
Put the blueberries, grapefruit fillets, grapefruit juice, sugar, cinnamon and clove powder in a saucepan. Mix well and let steep for about 1 hour. Then add the fruit juice and cook for 3 minutes. During this time, stir 1 teaspoon cornstarch with a little cold water in a cup until smooth, add to the blueberries and bring to the boil.
Remove the compote from the heat, pour it into a bowl and serve lukewarm or chilled. It tastes very good with pancakes, semolina porridge, semolina slices or vanilla ice cream. The grapefruit creates a somewhat bitter taste.