Pick over, wash, and measure the blueberries. Put them in a heavy stainless-steel pan. Crush the bottom layer. Add (1/2 cup water). Cook over moderate heat simmering until almost tender.

Add, for each cup of blueberries, 3/4 to 1 cup heated sugar* Stir and cook over low heat until a small amount dropped on a plate will stay in place. Place in hot sterilized jars.

*Spread the sugar on a baking pan and heat in a very low oven.

Note: The parentheses around the 1/2 cup water mean "optional."