To make the masala spice mix, heat a large, dry pan over a low heat and toast the cumin and coriander seeds, the cardamom and cloves for 2 mins until fragrant. Remove the cardamom seeds from the pods, then transfer with the rest of the mix a spice blender and blitz to a powder (or use a pestle and mortar). Stir in the turmeric and chilli powder until combined.

Heat the oil in a pan over medium heat and toast the mustard seeds until popping. Add the onions and cook for 8-10 mins until golden and softened. Add the garlic, ginger and chilli, and cook for 1 min more.

Tip in the squash, tomatoes, potatoes and 6 tbsp water. Cover and cook for 15-20 mins until the squash and potatoes are tender, adding a splash more water if the pan becomes dry.

Add the spice mix and remaining veg, season and mix well. Cook for another 8-10 mins until the veg is cooked through but still has a bite. Once cool, will keep frozen for two months. Defrost thoroughly and reheat until piping hot. Stir in the yogurt and warm through gently – don’t boil, or the yogurt will split. Taste for seasoning, scatter over the herbs and serve.