Step 1To make the apple syrup, peel and core 1 of the apples. Set aside the flesh for another use. Combine the skin, the core, the sugar and three-fourths cup water in a medium saucepan over medium heat. Simmer for 15 minutes, until the syrup is reddish-pink. Cool and strain. This makes one-half cup (4 ounces) syrup, which can be stored in the refrigerator up to 2 weeks.
Step 2In a pitcher, combine the Calvados, lemon juice and 2 ounces apple syrup. Pour half the mixture into a cocktail shaker with ice and shake until chilled. Strain into two chilled martini glasses. Repeat with the remaining mixture and pour into another two glasses.
Step 3Make 4 thin slices by cutting horizontally through the center of the remaining apple. Float an apple slice in each glass and gently top each drink with 1 ounce of sparkling rose (do not stir).