In a large nonstick pot, heat oil over medium-high heat. Add onion and cook, stirring occasionally, for 5 minutes or until golden brown. Stir in curry powder and cook 1 minute.
In a small glass measuring cup, mix together 1/4 cup of the vegetable broth and the cornstarch. Set aside.
Into the onion-curry mixture, add the remaining 3/4 cup broth, 1 cup water, the tomato sauce, cauliflower, green pepper, carrots, chickpeas and salt. Stir to combine.
Spoon vegetable curry into bowls and serve with nan or pita; use the bread to soak up any juices.