Vegan lasagne

Name: Vegan lasagne
Prep time: 25 min
Cook time: 2 h
Total time: 2 h 25 min
Cuisine: Italian
Ingredients: 30g bag dried porcini mushrooms; 6 tbsp olive oil; 1 onion , finely chopped; 2 carrots , finely chopped; 2 celery sticks , finely chopped; 4 garlic cloves , sliced; few sprigs of thyme; 1 tsp tomato purée; 100ml vegan red wine (optional); 250g dried green lentils; 2 x 400g cans whole plum tomatoes; 250g pack chestnut mushrooms , chopped; 250g pack portobello mushrooms , sliced; 1 tsp soy sauce; 1 tsp Marmite; 6 tbsp plain flour; 900ml soya milk; 1 whole nutmeg , for grating; 12 lasagne sheets; 2-3 tbsp nutritional yeast (optional, adds cheesy flavour); green salad , to serve