1. Preheat oven to 325°F (160°C). Line bottom of a springform pan.
2. Mix graham cracker crumbs, pretzels, sugar, and melted butter. Press into pan.
3. Bake crust for 10 minutes, then cool.
4. In a bowl, beat cream cheese and brown sugar until smooth.
5. Add eggs one at a time, then vanilla, sour cream, and heavy cream.
6. Stir in ¼ cup of the butterscotch sauce.
7. Pour mixture into crust. Wrap pan with foil and place in water bath.
8. Bake 50–60 minutes or until center is just set.
9. Cool at room temperature, then chill overnight.
10. Before serving, drizzle with remaining butterscotch sauce.
11. Add whipped cream, toffee bits, and sea salt as toppings.