For cake batter, cream butter in a large mixer bowl until fluffy. Gradually beat in sugar until light and fluffy. Beat in eggs, one at a time, beating well after each addition. Stir in lemon peel and vanilla.
Combine dry ingredients. Blend in dry ingredients alternately with sour cream, beginning and ending with flour mixture. Mix well after each addition.
Gently fold in dried fruit.
For streusel, place all ingredients in a small bowl. Combine ingredients using a pastry cutter until mixture is crumbly. Spoon one-third of the batter evenly into well-buttered and floured 10-inch tube pan. Sprinkle with one-half of the streusel. Repeat. Spread remaining one-third of cake batter over streusel.
Bake for 55-60 minutes, or until a wooden pick inserted in center comes out clean. Let cake cool in pan 15 minutes. Remove from pan and cool completely on wire rack. Cover and store at room temperature up to five days. Cake may be made ahead of time and frozen up to two months. Thaw, wrapped in refrigerator.