• Lightly grease the bottom and sides of a 10-inch springform pan. Preheat the oven to 350°F.

Make the blondie base:

• Place the butter and milk powder in a medium saucepan. Cook over medium-low heat, stirring frequently, until the butter and milk powder are golden brown and have a nutty aroma. Immediately transfer to a large mixing bowl.
  150 g unsalted butter, 15 g milk powder
• Add the brown sugar and whisk to combine. Add the vanilla and eggs and whisk until fully incorporated and the mixture is syrupy and glossy.
  220 g brown sugar, 15 ml vanilla, 2 large eggs
• Add the flour, cinnamon, nutmeg, allspice and salt. Stir just until combined, then fold in the toffee bits.
  158 g flour, 1/2 tsp cinnamon, 1/4 tsp nutmeg, 1/8 tsp allspice, 4 g salt, 120 g toffee bits
• Spread the batter evenly in the prepared springform pan. Bake for about 25–30 minutes, until puffed and lightly golden brown. Set aside to cool slightly while preparing the cheesecake batter.

Make the cheesecake batter:

• In a large mixing bowl, beat the cream cheese until smooth and creamy with no lumps.
  680 g cream cheese
• Add the sour cream, heavy cream and cornstarch and mix just until smooth.
  120 g sour cream, 60 ml heavy whipping cream, 9 g corn starch
• Add the caramel sauce, brown sugar, granulated sugar, cinnamon and nutmeg and mix until combined.
  67 g brown sugar, 60 g sugar, 160 g apple cider caramel sauce, 1/2 tsp cinnamon, 1/4 tsp nutmeg
• Add the eggs one at a time, mixing just until each is incorporated. Avoid overmixing once the eggs have been added.
  3 large eggs
• Mix in the vanilla and salt just until combined.
  15 ml vanilla extract, 3 g salt
• Pour the cheesecake batter evenly over the blondie base. Place the springform pan in the silicone cheesecake wrap, then set it inside the roasting pan.
• Place the roasting pan in the oven and add hot water to the fill line on the cheesecake wrap, or until the water reaches about halfway up the sides of the springform pan.
• Reduce the oven temperature to 300°F and bake for about 50–60 minutes, until the outer edge is set and the surface looks dry rather than wet or glossy. The center will still look underbaked at this stage; this is expected.
• Carefully remove the cheesecake from the oven and gently distribute the caramel apple pie filling evenly over the top. Start toward the outer edge and work toward the middle.
  1.2 kg caramel apple pie filling
• Return the cheesecake to the oven and bake for another 20–30 minutes. When done, the cheesecake should be set around the edges, with a gentle jiggle remaining in the center when the pan is lightly shaken.
• Turn off the oven, prop the door slightly open, and allow the cheesecake to cool in the oven for about 1 hour.
• Remove from the oven and allow to cool to room temperature. Transfer to the refrigerator and chill until completely set, at least 8 hours or overnight.
• When serving, drizzle individual slices with additional caramel sauce if desired and/or garnish with whipped cream.