Cut bread into cubes 1/2-inch to 3/4-inches in diameter; place in a large bowl; let sit out about an hour to dry; the drier the bread cubes, the more custard mixture they will soak up.
Pre-heat oven to 350°F and spray a 9-inch x 13-inch baking pan with non-stick cooking spray; set aside.
In a medium bowl and using a wire whisk, mix the eggs, sugar and vanilla until well combined.
Add in milk and heavy cream; mix well.
Pour egg mixture over bread cubes; mix gently and allow to sit about 15 minutes; mixing occasionally.
In a microwave safe bowl, or a small sauce pan, melt butter.
Remove from microwave; add brown sugar and mix until sugar is dissolved.
Add 1/4 cup of heavy cream; stir until well incorporated.
Add pecan halves; stir until combined.
Pour pecan mixture over the bread and egg mixture; gently fold.
Do not mix thoroughly; just fold so the pecan mixture forms into clumps throughout the bread pudding.
Pour bread pudding mixture into prepared baking pan; spread evenly.
Place in the pre-heated oven and bake for 45 to 55 minutes, or until the top is slightly brown and crisp; the center should still be a tad jiggly.
Remove from the oven and allow to cool at least 20 minutes before serving.
The egg mixture will continue to cook and the bread will soak up even more of the yummy custard mixture.
