Preheat oven to 350°F. Butter or grease a 9x13-inch baking dish.
Grease baking dish, Cut up bread and add into the dish. Set aside
In a large bowl, Make custard mixture
Whisk together eggs, milk, heavy cream, brown sugar, sugar and vanilla
Mix until fully smooth and combined.
Pour custard mixture over bread cubes. Add ½ cup chopped pecans and gently fold until all bread is evenly coated.
Let sit for 15 minutes so the bread fully absorbs the custard.