Bring milk to the boil in a medium saucepan; remove from heat.

Meanwhile, whisk egg yolks and sugar in a medium bowl with an electric mixer until creamy; gradually whisk into hot milk. Return to heat, stir over low heat, without boiling, until mixture thickens slightly.

Transfer mixture to a large heatproof jug or bowl; cover surface with plastic wrap. Cool, then refrigerate until cold.

Stir passionfruit into cold custard, then stir in cream.

Pour mixture into a shallow cake pan, cover with foil; freeze 3 hours or until almost set.

Beat coarsely chopped ice-cream in a large bowl with an electric mixer until smooth; return to cake pan. Cover; freeze until firm