Place clean black raspberries in the bowl of a food processor and puree until the berries look soup-y and the seeds look to be the only solids. (about a minute and 30 seconds)

Place a fine mesh strainer over a bowl. Pour the pureed berries into the strainer and press the mixture through the strainer until only the seeds remain. Discard the seeds.

To the black raspberry puree, whisk in the yogurt, sugar and lemon juice until smooth. Cover with plastic wrap and cool in refrigerator at least 2 hours.

Once cooled, pour into ice cream maker and freeze according to manufacturers directions.