Stir blackberries in a medium pan over low heat until berries start to break down.
Stir in vanilla extract and cream cheese until cream cheese is melted and mostly incorporated with berries.
Remove berry mixture from heat and let cool to room temperature.
In a large, chilled bowl, beat heavy cream until soft peaks form.
Mix sweetened condensed milk into heavy cream until fully incorporated.
Add berry mixture into cream mixture and stir until fully incorporated.
Gently stir in entire graham cracker crust - do not fully incorporate the crust - chunks are fine here.
Pour ice cream mixture into a 9x5 loaf pan. Cover with plastic wrap and freeze for a minimum of 6 hours, preferably overnight.