Cook the potatoes in salted water, mash them with soy milk. Season with salt, pepper and nutmeg and set aside.
Brown the onion and garlic in a skillet. Add the soy beans, then the diced tomatoes, coulis and oregano. Simmer for 20 to 30 minutes.
Build the mince, starting with a layer of mashed potatoes, then a layer of soy beans with tomato, a layer of spinach (thawed) and finish with potatoes.
Mix breadcrumbs, nutritional yeast and yogurt and spread over the preparation.
Place in the oven for 30-40 minutes, serve hot.