Place the diced onion, crushed garlic, ginger puree (or grated ginger), chopped cherry tomatoes in the slow cooker pot.
Add all the spices (1 teaspoon each of garam masala, turmeric, cumin seeds, ground coriander, paprika, chilli powder, salt) and two tablespoons of tomato puree, and mix.
Add the sliced red pepper, chopped courgette and diced turkey breast and stir well so the vegetables and turkey breast are coated in the curry paste you have made following the steps above.
Cook on high for 3-4 hours or on low for 6 hours.
Fifteen minutes before the end of cooking, add the two more tablespoons of tomato puree and half the fresh chopped coriander. Stir, then add 50 g of fresh spinach.
Cook for a further fifteen minutes then serve garnished with the rest of the chopped fresh coriander.