Preheat the oven to 180°C.
First make the sauce. Peel and chop the sweet potatoes and scatter them in a baking tray. Cut the red pepper into chunks, the onion into wedges. Add these to the tray together with the garlic cloves (unpeeled).
Mix the oil and spices, then pour over the vegetables and toss dwell. Season to taste, then bake in the oven for 25 minutes or until they are tender.
Take the tray out, remove the skins of the onion and garlic.
Transfer the veggies to a saucepan and add the passata. Bring to the boil, then turn off the heat. Add the fresh herbs and mash the stew with a fork, or process it with a hand-held blender into a textured, thick sauce. Drain the chickpeas and add to the sauce. Taste and season to your liking.
Cut out the stalks of the mushrooms, then chop these finely and add to the sauce.
Rub the mushrooms with a little oil, then put them on a baking tray.
Stuff the mushrooms with the stew and scatter some grated cheese on top .
Bake in the oven for about 15 minutes or until the cheese has melted.
Serve warm.