01 -  Preheat oven to 400°F (200°C). 
 02 -  Melt 1/2 cup granulated sugar in a 9-inch ovenproof skillet or tarte Tatin pan over medium heat without stirring, swirling gently until it turns deep amber. 
 03 -  Add 1/4 cup unsalted butter, vanilla extract, pinch of salt, and cinnamon if desired; stir until smooth. 
 04 -  Arrange apple quarters cut side up, packing them tightly in the pan. Cook over medium, basting occasionally, for 12–15 minutes until apples soften and caramel thickens. Remove from heat. 
 05 -  Roll out puff pastry to slightly larger than the pan diameter. Drape pastry over apples, tucking edges down around the fruit. 
 06 -  Bake for 25–30 minutes or until pastry is golden brown and crisp. 
 07 -  Line a baking sheet with parchment. In a small saucepan, combine 1/3 cup sugar and 1 tablespoon water; cook over medium heat without stirring until golden amber. Stir in sea salt and crushed candies, pour onto prepared sheet, cool, and break into shards. 
 08 -  Allow tart to cool for 5 minutes, then carefully invert onto a serving plate while still warm. 
 09 -  Before serving, scatter candy crunch shards over the tart for texture and sweetness.