Heat oil in a pan and add cumin seeds, cardamoms, cinnamon, garlic, ginger, and chili. Sauté briefly until fragrant.
Add onions and cashews with ½ cup water. Cook until the onions are soft and translucent.
Blend this mixture into a smooth puree and set aside.
In the same pan, melt butter and add methi leaves and peas. Sauté for 2 minutes.
Pour the prepared puree back into the pan. Add salt, coriander powder, fennel powder, garam masala, and water or milk. Simmer for 8-10 minutes.
Stir in heavy cream and cook until the curry becomes thick and creamy. Adjust seasoning and serve hot.