Coat a 9 x 13-inch baking dish with cooking spray.
Arrange the bread slices in one layer in the baking dish.
In a large mixing bowl, add the eggs, milk, nutmeg, vanilla and ¾ cup of the brown sugar, stirring well to mix.
Pour mixture evenly over the bread.
Cover and refrigerate at least eight hours or overnight.
When ready to bake, preheat the oven to 400° F.
In a small saucepan over medium heat, melt the butter or margarine and add the remaining ¼ cup brown sugar, stirring well.
Top the egg mixture with the pecans and blueberries, then drizzle with the melted butter and sugar mixture.
Bake for 45 minutes until set and golden brown on top.