Cream butter; gradually add 1/3 cup sugar and 1 egg, beating well. Gradually add flour, stirring until well blended. Firmly press mixture into bottom and halfway up sides of a 9-inch Springform pan. Set aside.
Beat cream cheese at medium speed of an electric mixer until smooth; gradually add remaining sugar, beating well. Add 2 eggs, one at a time, beating well after each addition.
Combine pumpkin, spices, and salt; stir well, and add to cream cheese mixture. Mix well. Pour mixture into prepared pan. Bake at 350° for 50 minutes. Remove from oven, and let cool to room temperature; chill overnight. Remove sides from Springform pan.
Pipe whipped cream in a decorative design around base and on top of cake. Garnish with pecans.