Combine the cream, sweetened condensed milk and lemon juice into a large bowl. Using electric mixers beat the mixture until stiff peaks form.
Stir in the cocoa.
Transfer into a 9 cup capacity container. Cover and freeze until solid.
VARIATIONS: Stir through a cup of chocolate chips to make double chocolate! Add a teaspoon of vanilla essence instead of chocolate to make vanilla ice cream. Or swirl though a cup of caramel sauce or raspberry sauce!