Step 1

Combine the blackberries, 1/4 cup of the sugar and the lemon juice in a saucepan. Cook over low heat until the blackberries are broken down and syrupy, about 20 minutes.

Step 2

Pour the mixture into a bowl through a fine mesh strainer. Using a whisk or spoon, force out as much of the deep purple liquid as you can, and then set it aside to cool. Discard the blackberry pulp and seeds.

Step 3

Heat the half-and-half and remaining 1 cup sugar in a saucepan over medium heat.

Step 4

Using a whisk, beat the egg yolks until pale and thick. Temper the eggs by splashing a small amount of the warm cream into the yolks, whisking constantly. Pour the tempered yolks into the saucepan, stirring gently. Cook over medium-low heat until thick, stirring constantly, about 5 minutes.

Step 5

Pour the heavy cream into the bowl with the berries, and then pour in the custard and stir to combine. If you have time, refrigerate this mixture until cool.

Step 6

Freeze the mixture according to your ice cream maker's instructions.

Step 7

When it is frozen, chop the chocolate into chunks and stir into the ice cream.

Step 8

Transfer the ice cream to a freezer-safe container and allow it to harden for several hours or overnight.