Heat the vegetable oil in a balti dish or large frying pan over medium heat.

Add the chopped onion and cook until softened, about 5 minutes.

Stir in the minced garlic and cook for another minute.

Add the diced red and green bell peppers, sliced carrot, and cauliflower florets to the pan. Cook for 5-7 minutes, stirring occasionally, until the vegetables are slightly tender.

Add the diced tomatoes, ground cumin, ground coriander, turmeric, garam masala, and chilli powder to the pan. Stir well to combine.

Pour in the water and season with salt to taste. Stir again, then reduce the heat to low and simmer for 15-20 minutes, or until the vegetables are cooked through and the sauce has thickened slightly.

Garnish with fresh coriander leaves before serving.