Preheat oven to 350 degrees. Line a 12-cup muffin tin with papers or spray with nonstick cooking spray. In a large bowl, whisk together the flour, baking powder, baking soda and salt.
In a separate bowl, whisk together the buttermilk, sugar, eggs, oil, lemon juice, lemon zest and vanilla. Pour the buttermilk mixture into the dry ingredients and stir until combined. Gently fold in the blueberries. Fill the muffin tin 2/3 of the way.
In a small bowl, combine all of the ingredients for the crumble and stir with a fork. Sprinkle generously over top the muffin batter. Bake 30-35 minutes.