Step 1 — Sauté the base: Heat the oil in a large pot over medium heat. Add the onion and cook for 4–5 minutes until soft and golden. Stir in the garlic and ginger and cook for another minute.
Step 2 — Add the spices: Add curry powder, cumin, turmeric, coriander, and garam masala. Stir constantly for 30 seconds to let the spices bloom and release their aroma.
Step 3 — Build the sauce: Pour in the chopped tomatoes and coconut milk. Stir well, then add vegetable broth or water. Bring to a gentle simmer.
Step 4 — Add potatoes and chickpeas: Stir in the diced potatoes and chickpeas. Cover and simmer for 20 minutes, stirring occasionally, until the potatoes are tender and the sauce thickens.
Step 5 — Add spinach: Fold in the spinach and let it wilt for 2–3 minutes. Taste and adjust seasoning with salt, pepper, and a squeeze of lemon juice.