Cut bread into cubes; arrange on a baking sheet. Dry out at room temperature for about 1 hour.

Preheat the oven to 350 degrees F (175 degrees C).

Beat eggs together in a medium bowl. Stir in milk, white sugar, and vanilla until combined.

Place bread cubes in a baking pan; pour milk mixture over bread cubes.

Place butter in a microwave-safe bowl; microwave until melted. Stir in brown sugar until dissolved, then stir in pecans.

Pour pecan mixture over bread cubes; gently fold. Don't mix it in thoroughly, just fold it so pecan mixture forms clumps throughout bread pudding.

Bake in the preheated oven until top is slightly brown, 45 to 55 minutes. The center will still be a little jiggly.

Cool before serving, at least 20 minutes.