Preheat oven to 325° F. Grease and flour a 10-inch Bundt cake pan. Set aside.
In large mixing bowl, cream butter and sugar. Add sour cream and mix just until incorporated.
Sift baking soda, cinnamon and flour together. Add flour mixture to sour cream mixture, alternating with eggs. Beat each egg one at a time.
Add vanilla and pour mixture into prepared baking pan. Bake for approximately 80 minutes, or until toothpick inserted in middle comes out clean.