To the same pan, add 1 tablespoon oil. Once hot, add chopped onions. Cook, stirring occasionally, for 2-3 minutes or until onions are soft and translucent.
Add garlic and ginger. Saute, stirring, for 1 minute or until fragrant.Add ground cumin, garam masala, red chili powder, butter and lemon juice. Sauté, stirring, for 1 minute or until aromatic.
Add tomato paste, cream, yogurt and milk. Stir to combine. Bring to the boil. Simmer for 2-3 minutes.
Add chickpeas and ground cashews (if using). Stir to combine.
Simmer for another 3-4 minutes. Remove from heat.Garnish with coriander (cilantro) leaves.