```markdown
Ingredients:
- 300g pumpkin, steamed and mashed
- 500g all-purpose flour
- 7g instant yeast
- 10g sugar
- 5g salt
- 200ml warm water
Instructions:
1. In a bowl, mix the warm water, sugar, and yeast. Let it sit for 5 minutes until foamy.
2. In a large mixing bowl, combine the flour, mashed pumpkin, and salt.
3. Gradually add the yeast mixture to the flour mixture and knead until a smooth dough forms.
4. Cover the dough with a damp cloth and let it rise in a warm place for about 1 hour, or until doubled in size.
5. Punch down the dough and divide it into small balls.
6. Shape each ball into a round bun and place on a baking tray lined with parchment paper.
7. Let the buns rise for another 30 minutes.
8. Preheat the oven to 180°C (350°F).
9. Bake the pumpkin buns for 20-25 minutes, or until golden brown.
10. Serve warm and enjoy your delicious pumpkin mantou!
```