Preheat oven to 350 degrees.
Combine flour, baking soda, salt and cinnamon in a medium size mixing bowl.
In another bowl, add oil, egg, sugar and milk. Stir well to combine.
Add wet ingredients to the dry ingredients and mix until just combined.
Gently fold in blueberries.
Scoop muffin batter 1/3 full and sprinkle with 2 tsp. crumb mixture (recipe below). Top with remaining 1/3 batter and another sprinkle of crumb mixture.
Bake for 20-25 minutes until done. Cool and eat.