In a mixing bowl, add the graham cracker crumbs, sugar, and melted butter. Stir until the butter coats all the crumbs.
Press the crumbs into a 9.5-inch springform pan. Press the crumbs into the bottom of the pan.
Place in the oven and let bake for 15 minutes.
Remove from the oven and let cool.
In a mixing bowl, add in the cream cheese and granulated sugar. Mix until completely incorporated. Scrape the sides and bottom of the bowl and mix again to avoid any lumps of cream cheese in your batter.
Add in the butter rum flavoring and eggs one at a time. Mix each egg completely before adding the next. Also scrape down the bowl after adding each egg.
Add in the sour cream and heavy cream. Mix until incorporated.
Just before adding the cheesecake mixture, line the outside of the springform pan with heavy duty tin foil. I double wrap it to prevent the water from leaking in.
Pour the cheesecake filling into the cooled crust.
Place the springform pan in a slightly larger baking pan. Fill the outer pan with water. Fill it so it at least goes a quarter of the way up the springform pan. This will keep the cheesecake from cracking.
Place in the oven at 325 degrees and let bake for 1 hour and 20 minutes or until done. To make sure the cheesecake is done, give it a wiggle. If it slightly jiggles in JUST the middle like jello, then it's done. If it jiggles all over, it needs to bake longer. Turn off the heat and crack the oven door slightly. Let it cool in the oven for an hour or two. I kept mine in the oven for about 2 and a half hours and then placed it in the fridge.
Make the sauce and whipped cream after the cheesecake has chilled.
In a medium saucepan, add in the brown sugar and heavy cream. Place the pan over medium heat and stir frequently.
As soon as the sugar is dissolved, remove from the heat and stir in the butter and butter rum flavoring. It should only take about 1 to 2 minutes for the sugar to dissolve. I made my sauce crunchy by letting it stay on the heat for 3 minutes (on purpose).
Pour the sauce on top of the cheesecake and spread out.
In a mixing bowl, add in the heavy cream. Beat until soft peaks form.
Add in the powdered sugar. Continue to beat until it becomes thick.
Add the whipped cream into a piping bag with a 1M tip. Pipe swirls on top of the cheesecake.