Preheat oven to 350 degrees F. Grease and flour 12-cup Bundt pan.
For Streusel: Combine brown sugar, cinnamon and allspice in small bowl. Cut in butter with pastry blender or two knives until mixture is crumbly.
For Batter: Combine flour, cinnamon, baking soda and salt in medium bowl. Beat granulated sugar and butter in large mixer bowl until light and fluffy. Add eggs one at a time, beating well after each addition. Add pumpkin, sour cream and vanilla extract; mix well. Gradually beat in flour mixture.
To Assemble: Spoon half of batter into prepared pan. Sprinkle Streusel over batter, not allowing Streusel to touch sides of pan. Top with remaining batter. Make sure batter layer touches edges of pan.
Bake for 55 to 60 minutes or until wooden pick inserted in cake comes out clean. Cool for 30 minutes in pan on wire rack. Invert onto wire rack to cool completely. Drizzle with Glaze.
For Glaze: Combine sifted powdered sugar and 2 to 3 tablespoons orange juice or milk in small bowl; stir until smooth.
