Pressure cook chickpeas in enough water with a pinch of salt till soft. It will take 4 to 5 whistles to cook.
Drain the water (stock). Do not discard the water as we will use it later.
Heat a pan with oil. Add cumin seeds and let it sizzle.
Add grated ginger, green chilies and onions.
Sauté over medium flame till onion turns translucent.
Add the ground dry mango paste, cooked chana (chickpeas) and about 1/2 cup of water (stock) used for cooking the beans, salt and mix well.
Let it cook over low flame for 2-3 minutes.
Add tomatoes, red chili powder, chana masala powder, turmeric powder, mix well.
Close the pan with a lid and let it cook for 4-5 mins over low flame.
Add potatoes and at this stage if the masala is dry then add 1/2 cup of chana stock or water and mix well.
Once again close with a lid and let it cook over medium – low flame for another 3-4 mins till the curry comes together.
Aloo channa masala or Aloo Chole is ready.
Take off stove and transfer to the serving bowl.
Garnish with ginger juliennes.
Serve hot with chapathis, rotis, puri or naans.