- Wash all produce before cooking.
- Coarsely chop green tomatoes and stem blueberries.
- Pulse blueberries and tomato in a blender or food processor until mixture is smooth.
- Cook blueberry mixture, 1 cup water, and sugar in a Dutch oven over medium heat, stirring constantly, until sugar dissolves.
- Add remaining ingredients. Bring to a boil; cook, stirring constantly, until mixture thickens.
- Pour hot mixture into hot jars, filling to 1/4 inch from the top. Remove air bubbles; wipe jar rims. Cover at once with metal lids, and screw on bands.
- Process in boiling water; bathe for 10 minutes.
Substitute blueberries for strawberries to make a nice strawberry jam.