In a large pot heat the olive oil and add the diced onion. Let the onion cook for a few minutes before adding the garlic and spices. Stir in the spices and add the ginger and green lentils. Add the tomatoes and stock and let the soup come to a rolling boil before adding the hard veggies (e.g. carrots and sweet potatoes) and letting it cook for 15 minutes. Add in the softer veggies (e.g. zucchini, red peppers), cover and let the soup simmer for 20-30 minutes, until the lentils and veggies are soft. Try the soup and add salt and pepper to taste, before adding the leafy veggies. Cook for an additional 2-3 minutes before serving.