Heat the oil in a large saucepan over medium-high heat. When the oil is hot, add fenugreek seeds and fry until dark brown.
Reduce the heat, add onions and turmeric. Cook stirring frequently until the onion softens.
Add in potatoes green chilies, cumin and coriander powder, mustard, ginger, salt, cayenne pepper, and bamboo shoots and stir for some time.
Stir the tomatoes and continue cooking until the potatoes soften.
Add the drained, cooked black-eyed peas to the potato mixture.
Increase the heat to high,, add 2 cups of water and bring the mixture to boil.
Reduce the heat to medium-low, add bell pepper, cover, and cook, stirring from time to time until the black-eyed peas, potatoes and bamboo shoots are tender, and the sauce has thickened.
Add cilantro and lemon juice.
Add salt to taste. Transfer the mixture to a bowl. Garnish with cilantro and serve hot.