Simmered in caramel syrup, the apples soften and take on an amber translucence; spoon some over Cinnamon Ice Cream.
Toss together apples and lemon juice in a bowl; set aside.
Stir together sugar and water in a heavy skillet; bring to a boil, stirring to dissolve the sugar. Reduce the heat to low and cook, not stirring but swirling the pan, until the sugar turns a deep amber, about 5 minutes (if the sugar crystallizes, it will take longer, but will eventually melt and caramelize).
Remove the pan from the heat and swirl in butter. Transfer the apples to the pan, cover and return to low heat. Cook, stirring occasionally, until the caramel has dissolved and the apples are translucent, about 10 minutes. Stir in Calvados, if using. Serve warm.
1 fruit, 2 other carbohydrate