Sweet Potato Cheesecake
How to Make It
Special equipment: a 9-inch springform pan with 2- to 3-inch-high sides; heavy-duty foil (preferably 18-inches-long) or a 10-inch round cake pan (in addition to springform pan; see Tips)
For Crust: Preheat oven to 350°F with rack in middle. Lightly coat a 9-inch springform pan with 2- to 3-inch-high sides with nonstick cooking spray.
In a food processor, chop pecans until finely ground, then transfer to a medium bowl. Add graham cracker crumbs, light brown sugar, granulated sugar and salt; stir to combine. Add butter; stir together until mixture is evenly moistened. Transfer mixture to prepared pan; press firmly onto bottom and 1/4 inch up sides of pan. Bake crust until set, about 15 minutes. Cool crust in pan.
For Filling: Wrap 2 to 3 layers of foil over bottom and up outside of springform pan with crust, covering pan completely and crimping foil around inside edge of pan to make pan watertight. Alternatively, insert springform pan with crust inside a 10-inch cake pan before preparing waterbath around the 2 pans (see Tips). In the bowl of a stand mixer fitted with the paddle attachment, combine cream cheese, granulated sugar, confectioners sugar and cornstarch; beat together on low speed for 30 seconds, then increase speed to medium; beat, scraping down sides once halfway through, until mixture is creamy and smooth, about 3 minutes. Add yogurt; beat, scraping down sides of bowl once halfway through, until well combined, about 3 minutes more. Add whole eggs and yolks 1 at a time, beating until blended after each addition. Add vanilla, salt and cinnamon; beat until well blended. Scrape down sides of bowl, then add purée; beat until well combined, 1 to 2 minutes more.
Transfer filling to baked crust in pan. Place springform pan with cake in a large roasting pan. Add enough hot water to roasting pan to come halfway up sides of springform pan. Bake until cheesecake is set around edges and center no longer moves when pan is gently shaken, about 1 hour 30 minutes. Transfer cheesecake in roasting pan to wire rack; cool completely in roasting pan. Remove cheesecake from waterbath; remove foil from springform pan. Chill cheesecake in springform pan uncovered at least 4 hours or overnight.
Using small knife, cut around cake sides to loosen. Remove pan sides. Cut cake into wedges and serve.
Note: To make sweet potato purée, wrap 1 1/2 pounds sweet potatoes in foil; place in a baking dish. Roast at 400º on middle rack until very soft, about 1 hour 30 minutes. Unwrap, let cool, then peel. Discard skins. Purée flesh in a food processor until smooth. Purée can be made up to 3 days ahead. Keep covered and refrigerated until ready to use.
Tips: To best seal a springform pan with foil when baking a cheesecake in a waterbath, use a springform pan without a lip. A lip-free pan allows for a tighter foil wrap, which helps guard the pan from both water and condensation while the cake bakes. Alternatively, you can simply place the 9-inch springform pan into a 10-inch round cake pan or high-sided skillet before preparing the waterbath around the 2 pans. As long as the space between to the two pans is minimal, any condensation that forms between the 2 pans while the cake bakes will quickly evaporate.