Pumpkin-Chocolate Cheesecake

Preheat oven to 350°F with a rack in center. Bring a small pot of water (about 8 cups) to a boil. Assemble a 9-by-3-inch springform pan with raised side of bottom part facing up.

For the Crust: In a food processor, grind wafers until fine (you should have 1 1/3 cups). Add butter, sugar, and salt; pulse until evenly moistened. Press evenly into bottom and 1/2 inch up sides of pan. Refrigerate 10 minutes. Bake until fragrant and firm, about 12 minutes. Let cool on a wire rack; reduce oven temperature to 325°F.

For the Filling: Meanwhile, beat cream cheese and sugar on low speed until smooth; add flour and beat to combine. Add pumpkin, cinnamon, ginger, vanilla and salt; beat to combine. Beat in eggs, one at a time, beating to combine after each addition.

Wrap springform pan in foil (to keep water from seeping in during baking); place in a roasting pan. Pour filling into crust. Place roasting pan in oven, add boiling water to come halfway up sides of springform pan. Bake until pie is puffed around edges and just a tiny bit wobbly in center, about 1 hour, 15 minutes. Transfer springform pan to wire rack; remove foil and let cool 20 minutes. Run a paring knife around edges and let cool completely on rack, about 4 hours. Transfer pan to refrigerator; cover loosely and chill at least 8 hours and up to 2 days.

For the Caramel: Release sides of pan and remove cake. Cook sugar and 2 tablespoons water in a small saucepan over medium-high heat, stirring until sugar has dissolved. Stop stirring and cook, swirling pan occasionally and brushing down sides of pan with a wet pastry brush, until amber, 3 to 5 minutes. Remove from heat and stir in cream and salt (it will bubble up). Return to heat and simmer 1 minute, stirring to dissolve any hardened caramel. Stir in chocolate. Let cool 20 minutes, then pour over cake.

Return cake to refrigerator until set, at least 30 minutes and up to overnight. For the cleanest slices when serving, use a knife dipped in hot water and wiped dry after each.