Coat a 9x13" baking dish with cooking spray. Cut bread into 2" cubes and place in pan.
In a large bowl whisk eggs, milk, cinnamon, vanilla and 1/2 c. brown sugar. Pour evenly over bread.
Cover and chill overnight in refrigerator.
In the morning preheat oven to 350 degrees.
Sauté pecans in 1 tablespoon of butter for a couple of minutes. Add the pecans and blueberries evenly over bread mixture; work into bread cubes a little bit.
Sprinkle 1/2 cup brown sugar over the top and dab 1/4 cup butter on top of brown sugar.
Bake loosely covered with foil for 55 minutes. Uncover and bake another 20 minutes until liquid is absorbed and top is golden brown. Let stand for 5 minutes before serving.
Serve with breakfast syrup, maple syrup or blueberry syrup.