Heat 1 tbsp of oil in a large lidded pan over a medium heat and cook the onion for 10 minutes until soft, without browning, then add the diced squash and garlic. Cook for 8-10 minutes until softening at the edges. Add the spices, coat everything well, stirring for a minute or so. Season generously, then add in the passata, sugar and 250ml of water. Stir, cover with a lid, reduce the heat and cook gently for 20-25 minutes (stirring occasionally and adding a splash of water if it begins to look a little dry) or until the squash has cooked through.
Remove the lid, stir well and add the beans, and most of the parsley.
In a separate small pan, heat 1 tbsp of oil and the dried mint over a medium heat for a few minutes, ensuring it doesn’t burn, then remove from the heat and set aside.
Serve the stew with dollops of yogurt, scattering over the remaining parsley and the hot mint oil.