Prepare rolls or bread according to directions on package. Once fully cooled, cut into 1 inch cubes and place in a greased 9x13 casserole dish.
Preheat oven to 350 degrees.
In a mixing bowl, combine eggs, milk, vanilla, sugar, salt, cinnamon, and nutmeg. Whisk until well combined.
Pour egg mixture evenly over cubed bread pieces. Top with blueberries.
In a small mixing bowl make the topping by mixing butter, brown sugar, cinnamon, and pecans. Sprinkle evenly on top.
At this point you can either bake it immediately or refrigerate overnight until ready to bake. If baking immediately, bake at 350 for 40-50 minutes or until puffed and golden and knife inserted in center comes out clean. If baking from the fridge, add 5-10 minutes to baking time.
Serve as is, or top with additional berries and drizzle with your favorite syrup.