Preheat the oven to 350 degrees. Grease and flour a tube/bundt pan.
In a large bowl, cream together the butter, sugar and eggs. Fold in the sour cream and vanilla carefully. Add the dry ingredients and mix well.
Spoon half of the batter into the prepared pan.
In a small bowl, combine the streusel ingredients. Sprinkle the streusel over the batter.
Spoon the remaining batter over the streusel.
Bake at 350 degrees for 50-55 minutes, or until a toothpick inserted in the cake comes out clean.
Allow the cake to cool for at least 35 minutes. Using a knife, loosen the edges of the cake from the pan.
Turn the cake out onto a plate. Cover until serving.
This cake is best when made the day before serving.
**If you'd like to serve the cake with the powdered sugar glaze, simply whisk the 3 glaze ingredients together, adding enough cream to make the glaze able to be drizzled. Drizzle over the cooled cake.
The calories shown are based on the cake being cut into 15 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate.