Wash, halve and core the apples. Grate and squeeze the lemon, bring the zest and juice to the boil with calvados and vanilla sugar. Add the apple halves and cook for about 5 minutes. Remove the apples from the brew and place in a baking dish. Reduce the brew by about half. Let the ice thaw.
Mix the marzipan mixture with the powdered sugar and about 3 tablespoons of the brew to a sprayable mixture. Fill the apple halves with a piping bag and grill the apples under the preheated grill.
Mix the ice cream and serve with the apples. Garnish with mint.
An alternative to calvados would be cider, as an alcohol-free variant, apple juice.