Butter and flour 9x9 or 8x11 baking pan. Preheat oven to 375 degrees.
For the coffee cake...
In a medium bowl, sift together dry ingredients (flour, baking powder and salt). In a large bowl, beat together eggs, oil, sugar, milk and vanilla.
Dust blueberries in flour then add to the large bowl. Slowly add the dry ingredients to the wet and stir until just combined. Allow to rest for 5 minutes. Pour into prepared baking pan.
For the topping...
Combine all ingredients then crumble evenly over top of batter.
Bake for 25 - 30 minutes. Cool in pan on wire rack for 10 minutes before serving.