Heat oil or ghee in a large skillet or sauté pan over medium heat. When hot, add cumin seeds (if using) and let them sizzle for 30 seconds. Add onions and cook until golden brown, about 6–8 minutes.
Stir in garlic and ginger. Cook for 1 minute until fragrant.
Add tomatoes, cumin, coriander, garam masala, turmeric, and ¼ teaspoon of the salt. Cook for 5–6 minutes, stirring occasionally, until the mixture thickens and pulls away from the pan edges.
Optional for a smoother curry: Cool slightly and blend this base into a paste before returning it to the pan.
Stir in green peas and coconut milk. If your coconut milk is very thick, replace ¼ cup of it with water. Bring to a simmer, cover, and cook for 8–10 minutes, until peas are tender and the sauce has thickened slightly.
Stir in lemon juice (optional) and remaining salt. Taste and adjust seasoning as needed. If you like, drizzle a bit of ghee or coconut oil over the top for aroma.
Garnish with chopped cilantro and serve hot with steamed rice, jeera rice, naan, or roti.
