1 ½tablespoonlime juiceor more/less to taste, can also use lemon
Instructions
Place the sugar and water in a small saucepan and place over a medium heat. Warm, stirring now and then to dissolve the sugar. You don't need to simmer, just warm enough to dissolve, then remove from the heat and allow to cool to room temperature.
Wash the blackberries well then place in a blender or food processor and blend to break the fruit up well. Press the mixture through a fine strainer, making sure you press through as much of the fruit pulp as you can. Discard the seeds and solids.
Add the strained blackberry puree to the cooled sugar syrup along with the lime juice and stir to combine and mix well. Chill in the fridge for at least an hour (or longer, if possible - overnight is good) so the mixture is well chilled.
Following your ice cream maker's instructions, pour the chilled blackberry mixture into the ice cream maker and churn until it reaches a soft-scoop consistency (around 20 minutes). Then, transfer to a container to freeze until firmer and for longer storage. It will likely need at least two or three hours to firm up. When you are ready to serve, you may need to let it sit a minute to soften slightly before scooping.
Video
Notes
If you don't have an ice cream maker, you can freeze the mixture in a container and remove from the freezer to break up ice crystals roughly every 30 minutes. As it is almost frozen, if it still looks to have larger ice crystals, you could pulse in the food processor to break up and be more even texture then freeze again to firm up.This is relatively sweet, as long as your berries are sweet, but they can vary. You might want to add around ¾ of the syrup first, taste, then see if you want to add the rest - it should be sweet (remember it dulls a little on freezing) but not sickly-sweet. You can also add more lime, if needed, as well.