Preheat oven to 325°F (160°C). In a medium bowl, combine the graham cracker crumbs and granulated sugar. Pour in the melted butter and mix until well combined. Press the mixture firmly and evenly into the bottom and slightly up the sides of a 9-inch springform pan. Bake for 8-10 minutes, or until lightly golden. Let cool completely on a wire rack.

In a very large bowl, using an electric mixer, beat the softened cream cheese on medium speed until completely smooth and lump-free (about 2-3 minutes). Add the packed light brown sugar, vanilla extract, and salt. Beat on medium-low speed until just combined. If using butterscotch schnapps/flavoring, add it now. Do not overmix. Add the eggs one at a time, beating on low speed until just incorporated after each addition. Scrape down the sides of the bowl as needed. Do not overbeat once eggs are added, as this can incorporate too much air and cause cracks. Gently fold in the sour cream until just combined.

Water Bath (Recommended for Crack-Free Cheesecake): Wrap the outside of the springform pan tightly with several layers of heavy-duty aluminum foil to prevent water from seeping in. Pour the cheesecake filling over the cooled crust in the springform pan. Place the foil-wrapped springform pan into a larger roasting pan. Carefully pour hot water into the roasting pan until it comes halfway up the sides of the springform pan. Bake for 60-75 minutes, or until the edges are set but the center (about a 2-inch circle) still jiggles slightly when gently shaken. Turn off the oven, crack the oven door, and let the cheesecake cool in the water bath for 1 hour. This helps prevent cracking. Carefully remove the cheesecake from the water bath, remove the foil, and transfer it to a wire rack to cool completely at room temperature. Once cool, cover loosely with plastic wrap and refrigerate for at least 6-8 hours, or preferably overnight, to allow it to set completely.

In a small saucepan, combine the packed light brown sugar, unsalted butter, and heavy cream. Cook over medium heat, stirring constantly, until the butter is melted and the sugar is dissolved. Bring to a gentle simmer and cook for 1-2 minutes, stirring occasionally, until slightly thickened. Remove from heat and stir in the vanilla extract and salt. Let the glaze cool completely to room temperature. It will thicken further as it cools.

In a cold bowl, using an electric mixer, whip the cold heavy cream, powdered sugar, and vanilla extract until medium-stiff peaks form.

Once the cheesecake is fully set, carefully remove it from the springform pan. Transfer the cheesecake to your serving platter. Pour the cooled butterscotch glaze evenly over the top of the cheesecake, spreading it to cover the surface. You can use a spoon to create swirls or patterns if desired, mimicking the picture. Transfer the whipped cream to a piping bag fitted with a star tip. Pipe dollops of whipped cream around the top edge of the cheesecake. Sprinkle the crushed butterscotch candies/toffee bits/graham cracker crumbs and chocolate chunks over the whipped cream dollops. Drizzle extra butterscotch glaze over the whipped cream and the top of the cheesecake, allowing some to drip enticingly down the sides. Slice with a sharp knife (dipped in hot water and wiped clean between slices for cleaner cuts) and serve chilled.