Blackberry Jam

Step 1
Mash blackberries in a saucepan with a potato masher. Stir in sugar until juices form. Remove 1 tablespoon blackberry juice from the saucepan; mix with cornstarch in a small bowl. Stir cornstarch mixture back into the saucepan.

Step 2
Bring blackberries to a boil. Once boiling, cook, stirring often, until jam has thickened, about 15 minutes. Stir in cinnamon and allspice.

Step 3
Remove from the heat and allow to cool, 30 to 45 minutes. Transfer jam to a bowl, cover, and refrigerate until chilled. Stir in lemon juice before serving.