Preheat oven to 350F
In a medium sized bowl, stir together the sugar, milk, oil, egg and vanilla extract and set aside.
In a separate bowl, combine the flour, baking powder, and salt. Add the dry ingredients to the wet ingredients mixture. Mix well.
Gently fold in the blueberries with a spatula.
Pour the batter into a greased 9" loaf pan.
Combine the streusel topping ingredients in a bowl, and use your finger to form crumbs. Sprinkle over the cake.
Bake for 60-65 minutes, until an inserted toothpick comes out clean and the crumbs are golden.
Cool for 15 minutes in the loaf pan before removing the cake and transferring it to a cooling rack.
