Directions:

1. Preheat oven to 375 degrees F (190 degrees C). Grease and flour a 9 inch pan or bunt pan.

2. Sift together the flour, baking powder and salt. Set aside.

3. In a large bowl, whisk together the oil, sugar and egg. Stir in the flour mixture alternately with the milk, mixing just until incorporated.

4. Beat for 2 minutes on medium speed.

5. Fold in the blueberries. Pour batter into greased bunt pan. Cover with streusel topping.

6. For the topping: In a bowl, combine 1/3 cup flour, cinnamon and 1/2 cup sugar. Cut in the butter until mixture resembles coarse crumbs.

7. Bake in the preheated oven for 40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.

8. For Icing: Melt butter. Combine milk, melted butter, vanilla in a small mixing bowl.  Slowly combine confection sugar with the mixture; stirring constantly. Add and stir in a touch of fresh lemon zest.

9. Drizzle icing over cooled cake.