To begin, preheat your oven to 350℉ and grease an 8 or 9 inch glass pie plate (either will work great for this recipe). I usually use a cooking spray to grease.
Combine the butter, sugar and egg in your mixing bowl, until creamy.
Combine the remaining blueberry buckle batter ingredients into a separate bowl – minus the milk.
Slowly add the remaining dry ingredients to your butter, sugar and egg mixture. Then, gradually add the milk until finished.
The last step for the batter is to fold in the blueberries. Because the batter is so thick, some of the blueberries may burst when you fold them in and that’s okay.
After you've mixed well, transfer the batter into the pie plate.
Mix Streusel Topping
Combine the streusel ingredients until they become a crumble consistency. I usually use a fork to mix it.
Once the streusel is combined, add the crumble to the top of the blueberry buckle batter.