Cut the melon into thick slices, remove the flesh from the skin and remove the seeds. Cut the flesh into small cubes. Sort the raspberries. Weigh 900 g melon cubes and mix with raspberries and jam sugar in a large, tall pot. Wash lemon thoroughly, dab dry and cut in half. Squeeze one half of the lemon, cut the other half into thin slices and then quarter them.
Add lemon juice and pieces of lemon to the prepared fruit. Bring to the boil while stirring constantly and let it boil fizzily for about 3 minutes. Make a jelly test (for this purpose put 1 teaspoon of the hot jam on a small plate and let it cool down). Fill prepared glasses to the brim with the hot jam and close them with twist-off lids. Immediately turn the glasses upside down and let them stand on the lid for about 5 minutes
Results in approx. 4 glasses of 450 ml capacity