Pre-heat oven to 375-degrees Fahrenheit.
Line a 9″x13″ baking pan with parchment paper (highly recommended since the berry filling exudes juices that will stick to the pan). But if you do not have parchment paper, grease the pan well.
- 2 sticks (1 cup / 8oz.) unsalted butter, softened
- 1 cup white sugar
- grated or chopped zest of 1 large lemon
Stir together in a bowl to combine– no need to whip air into the mixture.
- 1 egg
Add and stir to combine.
- 1/2 teaspoon salt
- 1 teaspoon baking powder
- 3 cups flour
Add all dry ingredients to butter-egg mixture and then stir to combine. Resulting “dough” / “batter” will be crumble-y.
Press 1/2 of the crumb-mixture into the bottom of the prepared 9″x13″ pan.
- 4 cups fresh blueberries
- 3 teaspoons cornstarch
- 1/2 cup sugar
- juice of the large lemon you zested
- 1/4 teaspoon salt
In separate bowl, stir to combine all of the above. Pour mixture over crumb-base in 9″x13″ pan.
Top with remaining crumb-mixture — trying to distribute as evenly as possible over berries. Press mixture gently into berries.
Bake 45 minutes at 375-degrees Fahrenheit. Rotate pan 180 degrees after 20 minutes, to ensure even baking in case your oven has hot spots. Remove from oven when berries are bubbling slightly, and crumb topping is slightly browned.
Allow to cool before cutting. Yield: 30-35 bars, depending on size.
These freeze and thaw wonderfully. So make several batches during blueberry season and freeze!