Chicken lasagne

If you are gluten free and don't eat red meat, it's difficult to find a lasagne that you can eat. We also eat lots of veg, so I decided it was time to get a decent lasagne dish, some gluten free lasagne sheets and bone and skinless chicken thighs. I made a large lasagne as the spare portions can either be frozen or taken to work for lunch.
This uses my "all-in-one" sauce method, so you will need a balloon whisk for this.
Ingredients (serves 6)
For the bolognese
1 onion, finely chopped
1 stick celery, finely chopped
1 tablespoon olive oil
1 pack chicken thighs, skinless and boneless - minced in a food processor
1 carrot, finely chopped
1/4 nutmeg, freshly grated
1/4 pint milk
2 tablespoons tomato puree
1 beef stock pot (trust me, it improves the flavour)
1 tin chopped tomatoes
1/2 tin water
Salt and pepper
1/2 teaspoon dried oregano
2 large chestnut mushrooms, halved and finely sliced.
For the white sauce
1 oz lacto free butter
1 oz plain gluten free flour
1 pint lacto free milk
Salt and pepper
Additional ingredients
12 sheets gluten free lasagne
1 tsp salt
1 large courgette, finely sliced lengthways
1/2 bag baby spinach leaves  (washed)
1 oz freshly grated parmesan

Method 
Bolognese
In a large pan, sauté the onion and celery in the olive oil over a gentle heat until the onion is translucent. Increase the heat and add the minced chicken, fry until all chicken has gone white, stir regularly. Add the carrots, nutmeg, milk and salt and pepper, cook for 1 minute,  then add the tomato puree, continue cooking until the liquid has evaporated.  Add the stockpot, oregano, tomatoes and the water, stir well, bring to a boil and then simmer for 30 minutes. Add the mushrooms and cook for a further 5 minutes.
Sauce
Take one medium pan and put all the sauce ingredients in the pan together. Put the pan over a gently heat and then keep stirring using a balloon whisk until the sauce is smooth and has thickened. Season to taste.
Pasta (only if using gluten free lasagne sheets).
Fill a large pan with water, bring to the boil and add the salt. Pop in the lasagne sheets and cook until al-dente. (I've tried using the sheets without pre-cooking and it doesn't work for the gluten free as well). If using normal quick cook lasagne sheets, you can omit this stage.
Build the lasagne
Take a lasagne dish and rub a little olive oil over the surface to prevent sticking.
Take a couple of large spoonfuls of the mince and spread them over the bottom of the dish, then drizzle over some of the white sauce, then a layer of lasagne sheets, next a layer of mince, then a handful of spinach, followed by a layer of courgette, plus another drizzle of white sauce.
Keep building the layers. You want to end with some mince and white sauce over the final layer of pasta. If you think you are running out of the white sauce, you can always add some more milk and thin it down towards the end.
Sprinkle over the parmesan cheese and then pop into a moderately hot oven Gas 5 (Electric 190C) for 40 minutes. It should be bubbly and golden on the top.
Serve with salad.