Heat oil in a large frying pan over medium-high heat.
Add onions. Sauté, stirring occasionally, for about 2-3 minutes or until browned.
Add garlic and ginger. Sauté, stirring occasionally, for 1 minute or until fragrant.
Add ground turmeric, ground cumin, ground coriander and red chili powder. Sauté, stirring, for about 30 seconds or until aromatic.
Add tomatoes. Cook, stirring occasionally, for about 2 minutes or until the tomatoes turn mushy.
Add chickpeas and chopped spinach leaves. Season with salt. Stir to combine. Cook, covered, for about 3-4 minutes.
Add spinach puree, coconut milk and garam masala. Cook, covered, for another 1-2 minutes.
Garnish with coriander (cilantro) leaves.
Top with sliced onions.
Serve with basmati rice or naan, and mango chutney, if using.