Preheat your oven to 400°F (200°C). Spread the pumpkin flesh evenly on a baking sheet and roast for about 20 minutes until it becomes fragrant and slightly caramelized. Allow it to cool slightly, then mash until smooth.
In a saucepan, bring water or milk to a gentle boil. Stir in the oats, a pinch of salt, and cook over medium heat, stirring occasionally, until the oats are tender and creamy, about 5-7 minutes.
Add the mashed roasted pumpkin and cinnamon to the cooked oats, stirring well to combine everything evenly.
Stir in the maple syrup, adjusting the amount to your preferred level of sweetness. Let the mixture simmer for another minute to meld the flavors.
Pour the oatmeal into bowls and drizzle with additional maple syrup if desired. Sprinkle a pinch of cinnamon on top for extra warmth and aroma.
Serve the warm oatmeal immediately, enjoying its velvety texture and cozy fall flavors.