Preheat the oven to 375 degrees F and set an oven rack in the middle position. Line a 9x9-inch baking dish with parchment paper (making sure you leave plenty of overhang so you can easily remove the bars) and spray the parchment paper lightly with nonstick cooking spray.
For the crust: In a medium bowl, combine the shortbread cookie crumbs, melted butter, brown sugar, and salt. Press into the bottom and barely up the sides of the prepared pan. Bake the crust for 10 minutes, remove, and set aside to cool. Reduce the oven temperature to 325 degrees F.
For the cheesecake batter: In a large bowl, (use a stand or hand mixer) beat the completely room-temperature cream cheese, sugar, and flour together on medium speed, just until smooth. Add in the sour cream, vanilla, and salt. Beat on low until combined. Be careful to not over-mix this batter and to keep the mixer at low, even speeds. Add in the eggs, mixing just until combined after each addition. Gently fold the Twix minis into the batter. (See Note 1.)
Pour the batter into the cooled crust and smooth into an even layer. Press down any Twix that may have popped above the surface. Bake for 38-43 minutes, until the center is just set and the top is not shiny (the center might still be a little jiggly, and that's perfect). Remove the bars from the oven and let cool at room temperature for 1 hour. After that, cover and chill in the fridge for 4-6 hours. (I always chill overnight and like that best!)
Lift the cheesecake out of the pan (using the parchment paper overhang) and using a very hot knife, slice into even bars. (I like to run the knife under very hot water, wipe it off, and then make one slice. Repeat until the cheesecake is all sliced!) Serve with caramel and chocolate sauce as desired. (See directions below.) The cheesecake is best when served right out of the fridge, so store cut bars in the fridge while you make the sauces. These cheesecake bars are best when served within 3-4 days after making.
Caramel Sauce and Chocolate Ganache
Chocolate Ganache: In a small saucepan, heat the heavy cream over medium heat and bring to a simmer; do not boil! Place the chocolate chips in a heat-safe bowl. Pour the simmering heavy cream over the chocolate chips and cover the bowl with the lid of a saucepan. Let stand for 5 minutes. Then remove the lid and stir for 2-3 minutes or until completely smooth. Let stand for a bit to firm up and then spoon over the bars.
Caramel Sauce: Place unwrapped caramels in a small saucepan over medium heat. Add the evaporated milk and heat, stirring constantly, until the mixture is smooth. Let stand for 5 minutes and then spoon over the bars.
Video
Notes
Note 1: Twix Minis: These are smaller than the full-sized Twix bars, yet larger than fun-sized candies. In order to have the right candy-to-cheesecake ratio, be sure to check the label and get the right size!