Aloo Gobi ki Subzi Potatoes and Cauliflower

Name: Aloo Gobi ki Subzi (Potatoes and Cauliflower)
Ingredients: 3 tablespoons vegetable oil; 0.25 teaspoon mustard seed; 1 pinch asafoetida powder; 0.25 teaspoon cumin seeds; 1 pinch ground turmeric; 1 hot green pepper, split down its length; 3 roma (plum) tomatoes, chopped; 2 tablespoons minced fresh ginger root; 1 potato, cubed; 1 head cauliflower, broken into small florets; 0.5 teaspoon white sugar; salt to taste