To make the simple syrup:
In a small pan over medium-high heat, bring the apple juice, caster sugar, fresh thyme, lemon peels and juniper berries to a boil. Reduce heat to low and simmer for 15 minutes.
Remove from heat and allow to “steep” for 30 minutes. Pour through a strainer and refrigerate until cold.
In a pitcher, add the spiced apple simple syrup, vodka, dry vermouth and lemon juice. Mix to combine.
Fill a cocktail shaker with ice cubes and add the martini. Shake until ice cold and pour into glasses.
Garnish with dried cinnamon apples and fresh thyme.