Toss diced apples in a bowl with 1/4 cup granulated sugar and ground cinnamon.

In a saucepan, combine remaining sugar with 2 tablespoons of water over medium heat. Stir until dissolved, then cook until golden brown. Remove from heat and stir in butter until melted.

In a mixing bowl, beat heavy whipping cream and vanilla extract until soft peaks form.

Gently fold whipped cream into cooled caramel mixture until well blended.

In serving cups, alternate layers of the apple mixture and caramel mousse. Chill for at least 2 hours before serving.