Bake at 350 Prepare a 10 inch tube pan with grease and flour. Bake 1hr.15min. check at 1 hour depends on your oven.
Cream butter and sugar and add the eggs one at a time. Combine the flour, baking soda, baking powder and salt and add alternately with the sour cream, mix well. Add the vanilla and beat until mixed thoroughly.
IN A SEPERATE BOWL: Mix streusel ingrediants.
Pour part of the batter in bottom of prepared pan, spread and sprinkle with streusel, repeat same again. Last layer is top, w/out streusel. Bake. Please check after 1 hour, my oven tests almost done at this point. This cake freezes beautifully also.