Preheat oven to 375 degrees Farenheit.
To prepare crust, combine pecans and graham crackers in bowl of a food processor; pulse to a fine crumb. Add sugar and butter; pulse to combine.
Spray a 9-inch springform pan with flour-based cooking spray. Press the crust mixture evenly in bottom of pan. Bake until browned, about 10-12 minutes. Let cool completely.
Peel sweet potatoes and cut in half lengthwise if they are large; place in a baking pan and brush with melted butter. Cover pan with aluminum foil and bake 45-55 minutes, or until they are cooked through and soft. Remove from oven and cool completely. Cut potatoes into 1-inch chunks and puree in food processor with lemon juice. Reserve 1 cup for cheesecake mixture; discard any remaining sweet potato or save for another use.
Reduce oven temperature to 325 degrees.
To prepare cheesecake batter, beat cream cheese until fluffy with mixer on high speed in a large bowl. Gradually beat in both sugars until well blended. Add eggs one at a time; beat well after each addition. Add in 1 cup pureed sweet potatoes, whipping cream, sour cream, maple sugar, cinnamon, nutmeg and ginger. Mix on low speed until well blended, making sure to scrape down sides of bowl throughout the process so that all ingredients are incorporated.
Wrap outside bottom of cheesecake pan in foil and press up sides to seal pan. Pour batter over crust. Set cheesecake pan in 12 x 15-inch roasting pan at least 3-inches deep and set pans in oven. Pour enough boiling water into the roasting pan to come halfway up the side of cheesecake pan. Bake 1 hour or until cake barely jiggles in middle when shaken. Remove cheesecake from water bath and refrigerate until firm, about 4 hours or overnight.
To serve, unclip springform collar and remove it from cheesecake; transfer cheesecake to a serving platter. Heat dulce de leche for 30 seconds in microwave or until loosened; drizzle over cheesecake. Place pecan halves around the top edge of the cheesecake.
Serve chilled; store cheesecake in the refrigerator.