Preheat your oven to 325°F (163°C). Line the bottom of a 9-inch (23cm) springform pan with parchment and lightly grease the sides.

Make the crust: In a medium bowl combine graham crumbs, 1/4 cup brown sugar, and melted butter. Mix until the texture resembles wet sand. Press firmly into the bottom and halfway up the sides of the pan. Bake for 10 minutes, then cool. Reduce oven temperature to 300°F (148°C).

Prepare the filling: In a large bowl, beat the cream cheese until smooth and creamy, scraping the bowl as needed. Add 3/4 cup brown sugar and the flour; mix until smooth. Stir in vanilla.

Add the dairy: Mix in sour cream and 1/2 cup heavy whipping cream until fully incorporated.

Melt 1 cup butterscotch chips in 20-second intervals in the microwave, stirring between bursts until smooth. Fold melted butterscotch into the batter.

Stir in the dry butterscotch pudding mix until combined. Add eggs one at a time, mixing slowly after each addition and scraping the sides. Do not overbeat.

Prepare the water bath: Wrap the exterior of the springform pan with aluminum foil to stop water leaks and place it in a larger roasting pan. Pour the batter into the crust and smooth the top. Put warm water in the roasting pan to come halfway up the sides of the springform.

Bake for about 1 hour 35 minutes, until the edges are set and the center still jiggles slightly. Turn the oven off and leave the cheesecake inside with the door closed for 30 minutes, then crack the door and leave for another 30 minutes.

Remove the cheesecake from the oven and water bath. Let cool at room temperature for 1 hour, then refrigerate at least 5–6 hours or overnight to fully set.

For the ganache: Place 1 cup butterscotch chips and 4 1/2 tbsp heavy cream in a heatproof bowl. Microwave in 15–20 second intervals, stirring until smooth and glossy. Pour over the chilled cheesecake and spread evenly. Sprinkle extra butterscotch chips for decoration. Chill at least 30 minutes to set the topping before slicing.