Attach wire whip to KitchenAid Stand Mixer. Add egg yolks and 3/4 cup sugar to mixer bowl. Turn to speed 4 and mix for 1 minute or until thick and sugar has completely dissolved. Reduce to Stir speed, gradually add milk and mix until well combined.
Pour mixture into a suacepan. Heat over medium-low heat, stirring constantly, for about 4 to 5 minutes, until hot but not boiling and coats the back of a spoon. Do not boil or it may curdle. Remove from heat and refrigerate until cold.
Exchange flat beater for wire whip. Add cream cheese and remaining sugar to bowl, turn to Stir speed and beat until smooth and creamy. Add lemon curd, and beat on Stir speed until just combined. Add cold custard and mix until smooth and combined. Transfer to a bowl and refrigerate until very cold.
Attach clean wire whip and bowl to mixer, add cream and whip on speed 8 until soft peaks form.
Fold in reserved cream cheese and lemon mixture.
Attach KitchenAid Ice Cream Maker attachment to mixer. Turn to Stir speed, pour mixture into freeze bowl and churn for 20 minutes or until soft set. While ice cream is churning, process cookies into fine crumbs. Stir in butter and set aside. Ice cream can be served immediately with cookie crumbs sprinkled over top or for a firmer texture, transfer to an air-tight container sprinkle with crumbs and freeze for several hours.