In a bowl, combine the first six ingredients; stir in butter. Press onto the bottom of an ungreased 10-inch tart pan with removable bottom.
In a mixing bowl, beat cream cheese and sugar until smooth. Add eggs, beating just until blended. Add pumpkin and 1/4 teaspoon cinnamon; beat on low speed just until combined. Pour into crust; sprinkle with walnuts and remaining cinnamon.
Bake at 350 degrees for 35–40 minutes or until center is almost set. Cool on wire rack for 1 1/2 hours. Refrigerate until serving.