Heat a wide heavy-based frying pan over medium heat. Add the oil and heat for 10 seconds or so, then add the onion and fry, stirring occasionally, until well-softened.
Tip in the spinach, sprinkle over the curry powder, raise the heat and stir, toss and fry until the liquid has mostly cooked out of the spinach and it is collapsed but still moist. Transfer to a large bowl.
Add the garlic, tomatoes, vegetable or tomato puree, breadcrumbs, chickpeas and peppers.
Season with salt and black pepper and mix well; it should be reasonably moist but not dripping. Stuff the filling firmly into the pepper halves, mounding up on top.
Bake in a low-sided dish at 400F for about an hour, turning the dish around once and lowering the heat towards the end if the peppers are getting too browned. This length of time makes the peppers deliciously soft - if you like them firmer, reduce the time.