Preheat the oven to 350ºF.
In a medium bowl, whisk together the sugar, milk, oil, egg and vanilla.
In a separate bowl, combine the flour, baking powder and salt. Add the dry ingredients to the wet ingredients and stir until just combined. Do not over mix!
Fold the blueberries gently into the batter.
Pour the bread batter into a greased and floured 9"x5" loaf pan. (You can line the pan with parchment paper if you'd like to ensure it removes easily.)
Make the crumble by mixing together the flour, sugar and butter in a small bowl. This mixture will be crumbly.
Sprinkle the crumbs evenly on top of the bread batter in the pan.
Bake for 55-60 minutes. The exact time will depend on the type of pan you have and your oven. A toothpick inserted in the center of the bread should come out clean.
Allow the bread to cool for 10 minutes, then remove the bread to a wire rack to cool completely.
Store at room temperature in an airtight container for up to 2 days or in the refrigerator for up to 4 days.