Preheat oven to 180°C fanforced (200°C conventional). Line 2 oven trays with baking paper. Use a small sharp knife to cut off tops from apples, about 1.5cm from the top. Use a melon baller or teaspoon to scoop out the core, seeds and most of the flesh from inside the apple, leaving a 1cm-thick side wall, and the base intact. Arrange apples on one prepared tray, and tops on the other.
Put cream cheese, sugar and vanilla in a large bowl and beat with electric hand beaters until smooth. Add egg and beat until incorporated. Fold in raspberries and spoon evenly into apples until just level with the tops. Bake for 18 minutes, add tray of apple tops and bake for a further 8 minutes.
Remove from oven and chill for 6 hours or overnight until cold. Scatter apples with crushed biscuits, then position apple tops. Serve.