Prepare Berries: Rinse and drain blackberries, removing stems and debris.
Combine Ingredients: Mix blackberries, sugar, lemon juice, and optional flavorings. Let sit 10–15 minutes.
Cook: Transfer to a heavy-bottomed saucepan over medium heat. Stir frequently and bring to a gentle boil.
Simmer: Reduce heat and simmer 20–30 minutes, stirring occasionally. Skim foam if necessary.
Test for Doneness: Use the cold plate test—if it gels and holds its shape, it’s ready.
Jar Preserves: Ladle into sterilized jars, leaving ¼ inch headspace. Seal tightly.
Cool and Store: Let jars cool at room temperature. Refrigerate for up to 3 months or process in a water bath for long-term storage
