Step 1

Bring 1 inch of water to a boil in a large pot fitted with a steamer basket. Add potatoes, cover and steam until tender, 6 to 8 minutes. Set the potatoes aside. Dry the pot.

Step 2

Heat oil in the pot over medium-high heat. Add onion and cook, stirring often, until soft and translucent, 3 to 5 minutes. Add garlic, curry powder, salt and cayenne; cook, stirring constantly, for 1 minute. Stir in tomatoes and their juice; cook for 2 minutes. Transfer the mixture to a blender or food processor. Add 1/2 cup water and puree until smooth.

Step 3

Return the puree to the pot. Pulse the remaining 1/4 cup water in the blender or food processor to rinse the sauce residue. Add to the pot along with the reserved potatoes, chickpeas, peas and garam masala. Cook, stirring often, until hot, about 5 minutes.