Preheat oven to 350F.
Slice pumpkin in half and remove seeds and pulp. Then peel pumpkin (I find it easiest to cut pumpkin into 1-inch wide slices first, then peel skin with a sharp knife), and chop into cubes.
In a bowl, add in the pumpkin cubes, onion, and garlic, along with the butter, olive oil, and maple syrup. Stir until pumpkin cubes are coated evenly.
Place the pumpkin mixture flat on a baking pan – use a plastic spatula to ensure all the liquid is transferred from the bowl to the pan. Tear the bay leaves into 4 pieces each and place between pumpkin cubes.
Put baking pan into oven and roast for 30 minutes, or until pumpkin cubes are softened. Let cool slightly.
Add chicken broth to blender. Then add in the cooked pumpkin – again using a plastic spatula to ensure all the liquid is transferred. Blend to desired consistency, and transfer to a pot on the stove.
Heat soup to a simmer, and stir in ancho chili powder, black pepper, and salt (and crushed pecans, if using). Taste and adjust any seasoning if needed. When thickened to desired texture, serve hot with a side of French bread.