Wash apricots well and pat dry. Pit them (keep the kernels) and dice flesh into 1cm cubes. Mix diced apricots with sugar in a large pot and let stand for at least an hour or preferably overnight in refrigerator. Add chopped kernels. Bring mixture to boil, stirring so it doesn't catch. It will rise in the pot with large bubbles. Skim off any scum that forms on top. Lower heat to a vigorous simmer until bubbles get smaller. Test for thickness by placing a few drops on a small cold plate (from refrigerator). When ready, remove from heat, stir in lemon juice and place in preserving jars following the maker's instructions.

Makes about a litre