Preheat oven to 400 degrees, and spray or line a 12 muffin cup tray and set aside.
In small bowl, combine 1/4 cup oats with brown sugar and set aside for topping.
In large bowl, combine remaining oats with the rest of the dry ingredients and mix well.
In small bowl, whisk together milk, eggs, yogurt, lemon zest and vanilla. Slowly add wet ingredients to the dry and stir until moistened- careful not to over mix.
Carefully stir in the blueberries and fill muffin cups 3/4 of the way. Sprinkle with topping. Bake 18-22 minutes or until light, golden brown.
Cool muffins in pan for at least 5 minutes. Remove from pan and serve warm.