Step 1: Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish with butter or non-stick spray.
Step 2: Place the dried brioche bread cubes into a large mixing bowl.
Step 3: In a separate medium bowl, whisk together the eggs, brown sugar, sweet potato puree, heavy cream, milk, vanilla, cinnamon, nutmeg, and salt until smooth.
Step 4: Pour the sweet potato custard mixture over the bread cubes and toss gently to ensure every piece is coated. Let it sit for 20-30 minutes to absorb the liquid.
Step 5: In a small bowl, toss the chopped pecans with the melted butter.
Step 6: Transfer the soaked bread mixture into the prepared baking dish and spread evenly. Sprinkle the buttered pecans over the top.
Step 7: Bake for 45-50 minutes, or until the custard is set and the top of the sweet potato and pecan bread pudding is golden brown and slightly crisp.
Step 8: Remove from the oven and allow to cool for at least 10 minutes before serving warm.