1. Begin by crushing the digestive biscuits or graham crackers finely using a food processor. Mix them in a bowl with melted butter until the mixture resembles wet sand.
2. Press the buttery crumbs firmly into the base of an 8-inch springform pan lined with parchment paper. Ensure an even layer, then chill the crust in the refrigerator for at least 30 minutes.
3. Beat the cream cheese with powdered sugar using an electric mixer until smooth and velvety. Add vanilla extract and salted caramel sauce, mixing until well incorporated.
4. In a separate bowl, whisk heavy cream until stiff peaks form. Carefully fold the whipped cream into the cream cheese mixture to achieve a light, airy texture.
5. Gently fold in chopped Twix bars to evenly distribute them throughout the filling. Pour this creamy mixture over the chilled crust, smoothing out the top.
6. Allow the cheesecake to set in the refrigerator for at least 6 hours or overnight to firm up.
7. For the chocolate ganache, gently heat heavy cream until steaming, then pour it over chopped semisweet chocolate. Allow the mixture to rest for a minute before stirring to a glossy smoothness.
8. Pour the ganache over the chilled cheesecake, spreading it evenly to the edges. Let the ganache cool and firm up in the refrigerator for at least 30 minutes.
9. Once the ganache has set, garnish the cheesecake with additional chopped Twix bars or drizzles of salted caramel sauce for added decoration.
10. Carefully remove the cheesecake from the springform pan and serve chilled.