It's a wonderful way to preserve an excess of fresh berries.
Place the berries and sugar in an enamel (or other non-reactive) pot. Bring to a boil, stirring occasionally, skim and remove foam that accumulates and discard.
Reduce heat and add lemon juice.
Allow to simmer for about 7 to 8 minutes, stirring frequently.
Using a slotted spoon, remove fruit to a clean small jar (or jars). Continue simmering juice, allowing it to reduce by about half, then pour over berries in the jar/jars dividing evenly if using more than one jar.
Allow to cool, cover and keep refrigerated.
This will keep about 3 weeks if kept covered and refrigerated. For longer storage it may be frozen. In that case use canning (or freezer safe) containers. This also makes a wonderful topping for ice cream, pancakes, waffles, or a simple cake such as a pound cake or Angel Food cake.