Dice potatoes into cubes and cut cauliflower into small florets.
Heat oil in a pan, crackle cumin seeds, and sauté chopped onion with ginger paste until golden.
Add potato cubes, cauliflower florets, turmeric powder, red chili powder, and salt.
Cover pan tightly and cook on low flame for 15 minutes, stirring occasionally until tender.
Serve warm with rotis.