Mushrooms and spinach lasagna

I penciled this recipe in my mom's recipe book a few years ago. I don't know where it came from. I have added mustard somewhere along the line as it makes the white sauce yellower and gives it a bit of a kick.

Serves: 4 persons.

Ingredients:

• 250g mushrooms, sliced (I used portobello because I like their flavour)
• 50g dried mushrooms (porcini, chinese, whatever you have at home)
• 200g baby spinach
• 1 onion
• 3 garlic cloves
• 1 bay leaf
• 250g mozzarella cheese, grated
• 50g pecorino / parmesan cheese, grated
• 6 sheets dried lasagna
• olive oil
• Salt and pepper to taste
• For the white sauce:
• 50g unsalted butter
• 50g plain flour
• 250ml water from the soaking of the dried mushrooms and cooking of the mushrooms and spinach
• 200ml milk
• 2 tbsp mustard
• nutmeg, salt and pepper to taste

Method:

1. Soak the dried mushrooms in hot water for at least 1h. Then slice them and reserve the water.
   
2. Fry the onions, garlic and bay leaf.
   
3. Add the mushrooms and let them cook. Do not be lazy like me! I diced instead of slicing the mushrooms and then I did not have space for all the mushrooms in the oven dish...
   
   
   
   
4. Add the cooked mushrooms to the soaked mushrooms and reserve.
5. Add a little water to the same pan and cook briefly the baby spinach. They cook under a minute so do not leave them!
   
   
   
   
   
   
   
    
6. Reserve the spinach.
   
7. Collect any water/moisture from the cooking of the mushrooms and the spinach, add to the water from the soaking of the mushrooms and reserve.
8. Prepare the white sauce: butter, then flour, then water and milk. Keep whisking the white sauce until it is thick and then add the mustard, nutmeg, salt and pepper to taste.
   
9. Coat the bottom of the ovenproof dish with the white sauce. This step's sole purpose is for the lasagna sheet not to stick to the bottom.
   
10. Place 3 sheets of lasagna on the bottom followed by white sauce, mushrooms, spinach and mozzarella. Make sure the white sauce coats all the lasagna sheets as it's the sauce that will re-hydrate the pasta and allow it to cook.
    
    
    
    
    
    
    
    
    
    
11. Another 3 sheets of lasagna followed by white sauce, mushrooms, spinach and the remaining mozzarella. Top with pecorino / parmesan cheese. I made a mistake of adding another 3 sheets of lasagna after this step but it doesn't need and it looks ugly when it is cooked (see pic step 12).
    
12. Bake for 30 min at 180°C until bubbly and golden.