• Place the blackberries, sugar and lemon juice in a medium sized pot.
• Mash everything together using a potato masher. I do not recommend using a food processor. In my opinion the best Jams have chunks of fruit and make the homemade appeal authentic and traditional.  
• Turn the stove top heat to medium-high. Stirring every few minutes and scoop out the foam. Cook for 3-5 minutes.  Turn down the heat to medium-low. Then simmer for an additional 10-15 minutes.
• Let the berries simmer until most of the juice evaporates. Then turn off the heat. The mixture will thicken after as the jam reaches room temperature.
• Once cool enough to touch; Transfer the contents to a jar or container and place in the refrigerator.

It’s good for up to 4-6 weeks.