Besides tinting the cake a lovely pale orange, sweet potatoes lend a pleasant texture to the rich, creamy filling. This recipe comes from Patty Pinner's cookbook Sweets (randomhouse.com).
Lightly grease the bottom and sides of a 9-inch spring-form pan; set aside.
For crust: In a large bowl, thoroughly mix together the graham cracker crumbs, sugar, and butter. Press mixture firmly into the bottom and 1 inch up the sides of the prepared pan.
For filling: In a large bowl, beat the cream cheese with an electric mixer on medium speed until light and fluffy . Beat in condensed milk, followed by sweet potatoes, until smooth. Add eggs one at a time. beating well after each addition. Add the 1/4 cup maple syrup, the cinnamon, nutmeg and salt. Beat until blended. Pour filling into crust in pan. (The filling will come higher than the crust.)
Bake in a 350º oven for 60 to 75 minutes, or until a 2 1/2-inch rim around outside edge appears set when gently shaken. Leave cheesecake in oven, but turn the oven off and leave the door cracked. After 1 hour, remove the cake from the oven and carefully run a small knife around the rim of the pan to loosen the cake. Let cake cool in pan on a wire rack for 2 hours, then transfer to refrigerator and chill, covered, overnight.
For topping: In a medium saucepan, combine 3/4 cup maple syrup and cream. Bring to boiling over medium heat, stirring often, until mixture thickens,about 15 minutes. Stir in pecans. Remove from heat; cool to room temperature.
To serve, remove sides of pan. Spoon some topping over the whole cheesecake. Pass remaining topping. Chill leftovers.