In a large, deep frying pan, heat up vegetable oil on medium heat and fry the cumin seeds for 30 seconds.
Add the sliced onions and brown sugar. Saute for 5 minutes, stirring occasionally.
Add rinsed and drained chickpeas (cooked or canned) and salt. Turn up the heat to medium-high and saute for 5 more minutes while stirring more regularly, until onions are translucent and starting to brown.
Turn heat back to medium and add garlic, ginger, and the ground spices - cumin, coriander, paprika, turmeric, cardamon, and cayenne, and fry for 2 minutes.
Add the chopped tomatoes and cook on medium heat for 10 minutes. Stir occasionally.
Turn the heat back to medium. Stir in the garam masala, then add the spinach and lemon juice. Cook for 2 - 4 minutes to let the spinach wilt down.Serve with rice, vegan naan, chapati or bulgur wheat and your favourite chutney.