Add water to a large saucepan over high heat. Once the water boils, add ½ teaspoon salt and ¼ teaspoon turmeric powder. Next, add 280 g cauliflower and 140 g potato (both cut) and cook for one to two minutes. Once done, drain the vegetables and set aside.
Add 3 tablespoons oil to a kadai or saucepan over medium heat. Once the oil heats, add 1 teaspoon black mustard seeds and wat for them to pop. Once they pop, add ½ teaspoon cumin seeds, 1 pinch asafoetida, 8 pieces curry leaves, and 80 g onion. Sauté these aromatics for a few minutes until the onion softens.
Next, add 2 teaspoons grated coconut and 40 g tomato. Continue to cook for another two minutes, then add sea salt (to taste), 1 teaspoon coriander powder, 3 teaspoon deggi mirch chill powder, and 1 teaspoon Maharashtran hot chilli powder. Continue cooking, stirring regularly, until the mixture becomes thick and jammy. The oil should separate.
Add the potatoes and cauliflower back into the pan, along with 300 ml hot water. Cook until the vegetables are soft (around five minutes), and the oil rises to the surface. Add ¼ teaspoon goda masala and turn off the heat.
Garnish with fresh coriander and serve hot with steamed rice, puri, or poli.