Mix raisins, butter, honey, and orange zest in a small bowl.
Stuff the raisin mixture into the cored apple and place on a microwave-proof plate.
Microwave on high for 3.5 minutes until the apple is softened.
Bring milk and cream to a boil in a saucepan then cool slightly.
Whisk egg, egg yolk, and sugar together in a bowl.
Pour the warm dairy mixture over the eggs and return to a saucepan over low heat.
Stir constantly until thick enough to coat a spoon and strain through a sieve.
Pour the warm custard over the baked apple to serve.