Blueberry Jam - cooking recipe

Ingredients

3 (1/3 ounce) envelopes unflavored gelatin
1 1/2 cups cold water
2 pints blueberries, mashed
3/4 cup sugar
2 tablespoons lemon juice
1 teaspoon butter or 1 teaspoon margarine
1/2 teaspoon ground cinnamon (to taste)
1/2 teaspoon vanilla extract

Preparation

In a large saucepan, combine the gelatin and water, and let stand for 1 minute.
Cook the gelatin/water over low heat about 5 minutes, stirring until dissolved.
Stir in the blueberries, sugar, lemon juice, butter and cinnamon.
Bring to a boil, over medium-high heat.
Boil for 10 minutes, stirring constantly.
Remove from the heat and stir in the vanilla.
Spoon into sterilized jars.