Heat oven to 400 F.Stir flour, 1/2 cup butter, 1/4 cup sugar, 1/2 teaspoon cinnamon and the egg yolk until mixture forms a ball. Pat about two-thirds of the dough on bottom only of 10-inch springform pan (with side removed) to make bottom crust 1/8 inch thick. Bake 8 to 10 minutes or until crust just begins to brown around edge.
Reduce oven temperature to 300 F. Attach side to pan. Pat remaining dough about 1 inch up inside of pan.
Beat sweet potatoes, 1 tablespoon butter, 1 teaspoon cinnamon, the nutmeg and vanilla in medium bowl with electric mixer on low speed until blended; set aside. Beat cream cheese and 1 cup sugar in large bowl on medium speed about 1 minute or until smooth. Beat in sweet potato mixture on low speed about 1 minute or until blended. Beat in eggs, one at a time. Pour batter into springform pan. Place springform pan in larger pan on oven rack. Pour very hot water into larger pan to one-third the height of springform pan.
Bake 1 hour 30 minutes or until center is set, adding very hot water to larger pan as needed.
Meanwhile, make Pecan Crumb Topping:
Stir flour, brown sugar, butter and cinnamon in small bowl until crumbly. Stir in pecans.
Sprinkle Pecan Crumb Topping over cheesecake. Bake about 30 minutes longer or until topping is set. Cool 30 minutes. Loosen side of cheesecake from pan; remove side of pan. Refrigerate uncovered 3 to 4 hours or until chilled. Serve with whipped cream if desired. Store covered in refrigerator.