This recipe from Smitten Kitchen is one of my favorites.
Ingredients:
- 1 cup white sugar
- 1 teaspoon baking powder
- 3 cups all-purpose flour
- 1 cup cold unsalted butter (2 sticks or 8 ounces)
- 1 egg
- 1/4 teaspoon salt
- Zest and juice of one lemon
- 4 cups fresh blueberries
- 1/2 cup white sugar
- 4 teaspoons cornstarch
Directions
1. Preheat the oven to 375 degrees F. Grease a 9×13 inch pan.
2. In a medium bowl, stir together 1 cup sugar, 3 cups flour, and baking powder. Mix in salt and lemon zest. Use a fork or pastry cutter to blend in the butter and egg. Dough will be crumbly. Pat half of dough into the prepared pan.
3. In another bowl, stir together 1/2 cup sugar, cornstarch and lemon juice. Gently mix in the blueberries. Sprinkle the blueberry mixture evenly over the crust. Crumble remaining dough over the berry layer.
4. Bake in preheated oven for 45 minutes, or until top is slightly brown. Cool completely before cutting into squares.
Needs More Butter 
I am so excited to try this one. I have been craving for some blueberries for quite some time now.
I love these so very much, they have magical powers of persuasion on people. They’re also good cold, but I generally think most baked goods are.