Method

• 1.
  Place pretzels in a food processor and whiz until finely chopped. Add biscuits and whiz until crumbs. Add 250g melted butter and whiz to combine. Press into base and side of a 22cm x 5cm-deep loose-based fluted tart pan. Chill until needed.
• 2.
  Place remaining 100g melted butter in a saucepan with brown sugar over medium-low heat. Stir until sugar has dissolved. Add thickened cream and simmer for 10-12 minute, until thick. Meanwhile, soak gelatine leaves in a bowl of cold water for 5 minutes to soften. Squeeze out excess water and stir into hot cream mixture to dissolve. Remove from heat and cool to room temperature.
• 3.
  In a stand mixer fitted with the whisk attachment, whisk cream cheese until smooth. Gradually add cooled cream mixture and whisk until combined. Pour into chilled tart pan and refrigerate for 6 hours, or until firm and set.
• 4.
  Meanwhile, for the crumble, preheat oven to 180°C/160°C fan-forced. Line a baking tray with baking paper. In a stand mixer fitted with the paddle attachment, beat butter, sugar, flour and vanilla gently for 1-2 minute, until a smooth dough forms. Add pecans and 1/2 tsp salt flakes and beat to combine. Break into 5cm pieces, place on prepared tray and bake for 20 minutes, or until golden. Remove from oven and cool completely. Crumble into smaller pieces.
• 5.
  Spread dulce de leche over cheesecake and scatter with crumble to serve