Heat the oil. Add the cumin seeds and let them cook for about 30 seconds or until they start to change color. Add the onions and a pinch of salt and ground black pepper. Saute, stirring frequently, until the onion starts to brown.
Add the ginger-garlic paste, stir-fry for 30 seconds, then add the meatless beef. Cook, stirring frequently and scraping the bottom of the pan to prevent it from sticking, about three to four minutes.
Add the potatoes and stir fry for a minute or two.
Add the tomato puree and the powdered spices, including the paprika, cayenne if using, turmeric, and coriander powder.
Let the tomatoes cook until most of the liquid has evaporated and bubbles form at the edges of the tomato paste mixture.
Add the black-eyed peas and bring the mixture to a boil. Add water if too thick.
Add green peas and garam masala and stir them in. Let the stew return to a boil and cook for two more minutes.
Add the lemon juice.
Check salt and add more if needed.
Turn off the heat and stir in the coriander leaves.
Serve hot with brown rice or quinoa or crusty bread.