Step 1

Heat 2 tablespoons of oil over medium-high heat in a large pot. Fry cumin seeds for a few seconds until they turn golden brown and begin to pop. Reduce heat to medium, stir in the onion, and cook until lightly browned. Stir in serrano pepper and ginger; fry for 1 minute. Season with coriander, paprika, turmeric, cayenne, and garam masala; cook for 30 seconds until fragrant.

Step 2

Stir potatoes and salt into the pot, cover, and cook for 5 to 7 minutes. Add cauliflower, cover, and cook until cauliflower steams in its own juices until tender, about 20 minutes. Stir in lemon juice. Pour remaining 1 tablespoon of oil around the edges of the pot. Increase heat to medium-high and fry for 3 to 5 minutes to brown, stirring gently to avoid mashing the cauliflower.