Water sauté onion in a large pot. Start with the dry pan over medium heat. Stir the onion until it just starts to stick a little to the pan, then add small amounts of water or broth, enough to keep the onions from sticking to the pan. Cook until translucent - about 5-10 minutes.
Add the garlic and cook 2-3 minutes, do not let it burn as that will impart a bitter taste.
Add the curry powder and mix well with the onions and garlic and allow to cook for a few minutes.
Add the garbanzos, sweet potato, tomatoes with juice, pumpkin, and coconut milk and mix together. Simmer until the sweet potatoes are tender. Stir frequently to keep the curry from sticking to the pot.
Taste for flavoring. Add salt and pepper as needed. I like my food spicy, so at this point I add a few shakes of other curry powders, as each mixture has its own unique taste, a good 2-3 dashes of cayenne pepper, and a heaping teaspoon of Thai red curry paste. This is one of those dishes you have to taste to get the seasonings right for your family.
If the mixture seems too thick, water or broth can be added until it reaches the consistency you like.