Prepare the chicken. Season the flour with plenty of freshly ground black pepper. Add the chicken pieces and mix well to coat all the pieces.
Heat the oil in a large pan over a medium heat, add the chicken and cook until browned on all sides, then remove and set aside.
Prepare the curryAdd the tablespoon of oil to the same pan, add the onion and cook for 5 minutes until softened and starting to turn translucent. Stir in the garlic, ginger, chillies, turmeric and garam masala and cook for 2 minutes, stirring continuously.
Add the tomatoes, stock, and browned chicken to the pan. Reduce to a simmer, cover and cook for 20 minutes, stirring occasionally.
Remove the lid, add the butter beans and simmer for another 10 minutes to allow the sauce to thicken and the beans to warm through. Taste and add more freshly ground black pepper if needed.
Scatter over the fresh mint leaves and serve immediately with wholegrain rice.