Combine 1/4 cup each vodka, apple brandy and apple cider in a jar; stir in half of a thinly sliced Granny Smith apple and 1 tablespoon sugar. Cover and refrigerate at least 2 hours or overnight. Pour a splash of absinthe into 2 martini glasses; swirl to coat. Fill a cocktail shaker with ice and add the vodka mixture, reserving the apple slices; shake well, then strain into the glasses. Add the reserved apple slices.