If using a pie pumpkin, cut it in half and scoop out the seeds. Bake the two halves face-down at 375° for 45 minutes, or until very soft.
Scoop out the cooked pumpkin from the skin and place in a blender or food processor and blend until smooth.
Add pumpkin to a large saucepan with the rest of the ingredients and cook over medium, stirring constantly and scraping the bottom of the pot to prevent sticking. When it just starts to bubble, turn it off.
Stir in rice dumplings and serve with sesame seeds and chopped pecans.
For the rice dumplings:
While pumpkin is baking, measure rice flour into a bowl and add hot water until a sticky dough forms. You should be able to pinch off pieces of dough and roll them into almond-sized dumplings without them falling apart or sticking too much to your hands. You may need to adjust the amount of water or flour.
Set dumplings aside and boil another pot of water.
Add dumplings to the pot and give them a stir to prevent sticking. Boil 10 minutes, then remove with a slotted spoon and set aside.
Add dumplings after the hobakjuk has finished cooking.