Heat oil in a large saucepan over medium heat. Add onion and bell pepper and cook, stirring, until the onions begin to color, about 5 minutes. Add jalapeno and ginger; stir for 1 minute. Stir in flour, curry powder and cumin and cook for 1 minute. Gradually whisk in broth; cook, stirring, until smooth and thickened, about 1 minute.