How to Make It
Heat the oven to 350°F. Make the crust: In a small bowl, toss together the graham cracker, Butterfinger, and salt. Add the butter and toss to combine. Transfer the mixture to a standard 9-inch pie plate or a 9-inch fluted tart pan and press against the bottom and sides to form a crust. Bake the shell until fragrant and set, about 12 to 14 minutes. Transfer to a rack to cool completely. Reduce the oven temperature to 325°F.
Make the filling: In a large bowl, with an electric mixer on medium, beat the cream cheese and sugar until smooth, about 2 minutes. Add the eggs, one at a time, and beat just until combined. Do not overmix. Fold in the sour cream and salt. Transfer the mixture to the prepared crust. Bake until just set (the center will be slightly wobbly), 25 to 35 minutes. Transfer to a rack to cool for 1 hour. Then wrap with plastic and transfer to the refrigerator to cool completely, 4 to 6 hours.
Make the topping: In a microwave-safe bowl, melt the chocolate and the butter together in short bursts, stirring often. To serve, top the cheesecake with the chocolate mixture and crushed Butterfinger.