Grind tomato to paste with the help of a blender. And keep aside.
For dry roasting
Heat half a teaspoon of vegetable oil to a pan over medium heat.
Add cauliflower florets and dry roast until it is half cooked. And set aside.
For making the base
In the same pan over medium heat, add vegetable oil and cumin seeds. And cook until it splutters.
Then add onion and cook till it turns soft and pink.
Now add tomato puree, and cook until the gravy thickens.
Add red chili powder, coriander powder, and turmeric powder. And in low heat, saute for a minute without burning the spice powders.
Add water. Turn to medium heat and allow it to cook over medium flame until the curry reaches desired flowing consistency.
Now add roasted cauliflower florets and diced green bell pepper.
Turn to low heat and cook for 3 minutes in low heat(to allow the veggie to infuse with all the flavors).
Top with a teaspoon of butter and serve hot.
Add a dash of salt while cooking onion and tomato for speedy and even cooking.You may add unsweetened coconut milk instead of butter to make South Indian style cauliflower curry.You may also use vegan butter instead of butter.