Preheat oven to 350 F and spray a 8 x 8 inch baking pan with non-stick baking spray.
In a medium bowl, combine milk, half and half, eggs, white sugar, vanilla extract, and salt and whisk vigorously to combine.
Add cubed bread to a large bowl and pour milk mixture over top. Let sit for about 10 minutes.
In a small bowl, combine butter, light brown sugar, and chopped pecans and stir with a fork until combined.
Pour half of the bread mixture into the prepared pan and top with half of the pecan topping.
Pour remaining bread mixture over top and top with the rest of the pecan topping.
Gently press down into the pan and place 8 x 8 inch pan onto a baking sheet.
Bake for 45-55 minutes, until bread pudding is set as desired.
Let cool at least 30 minutes in the pan before slicing and serving.
Baking for 45 minutes will result in a more soft and moist bread pudding, as baking for 55 minutes will result in a more set, crisp bread pudding.