Preheat your oven to 350°F (175°C). In a bowl, combine graham cracker crumbs, 1/4 cup of sugar, and 1/4 cup of melted butter.
Press this mixture into the bottom of a 9 1/2-inch springform pan.
Bake for 10 minutes, then remove and set aside, keeping the oven on.
Place the sweet potatoes in a baking dish and bake for about an hour, or until a knife easily pierces the center.
Once cool enough to handle, peel and puree the sweet potatoes. In a large bowl, beat together the cream cheese and 3/4 cup plus 2 tablespoons of sugar until smooth.
Add the sour cream, 1/4 cup of cream, and 1 1/2 cups of sweet potato puree, mixing until well combined.
Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Pour this filling over the prepared crust.
Bake the cheesecake in the preheated oven for about 1 hour, or until a tester inserted near the center comes out clean.
Turn off the oven and let the cheesecake rest inside with the door slightly open for 1 hour.
For the topping, melt brown sugar and 1/4 cup of butter or margarine in a small saucepan over low heat, stirring until the sugar dissolves.
Increase the heat to bring the mixture to a boil, then stir in 1/4 cup of cream and the nuts.
Pour the hot topping over the cheesecake.
Refrigerate any leftover cheesecake.