Preheat oven to 400º F and grease muffin tins or line with muffin liners.
Combine 1½ cups flour, ¾ cup white sugar, salt and baking powder in a mixing bowl and set aside.
Combine the egg, milk and vegetable oil in another mixing bowl.
Slowly combine the dry mixture into the wet mixture. The batter will be quite thick so try not to over-mix.
Fold in the blueberries and let the batter rest for 5 minutes.
Meanwhile, make your topping by mixing together ½ cup brown sugar, ⅓ cup flour, ¼ cup butter, and 1½ tsps of cinnamon with fork. DON’T MIX WITH YOUR HANDS! The residual heat will melt the butter and the crumb topping might burn or run off the muffins.
Next, fill the muffin cups ¾ of the way to the top with the batter, and then sprinkle with crumb topping mixture before baking.
Bake for 20 to 25 minutes and enjoy!