Prepare mushrooms: finely chop (either by hand or in a food processor - recommended) then in a large non-stick pan heat up 2 teaspoons of oil, add the mushrooms and soy sauce. Cook over a medium heat for several minutes until all the moisture has been absorbed and the mushrooms are nicely browned. Transfer to a bowl.
Make vegetable base: using the same pan heat up 1 tablespoon of oil, add the onion, celery and garlic and fry gently for about 3 minutes stirring often. Add the wine, increase the heat and cook for another minute or so.
Add ground turkey: add the meat and cook for a few minutes until it is no longer pink, stirring often.
Add passata: add the passata, tomato puree, Worcestershire sauce, balsamic vinegar, herbs, nutmeg, salt and pepper. Stir, cover and simmer for 10 minutes stirring occasionally.
Add vegetables: stir in the grated carrot, zucchini and mushrooms. Cook for another minute then remove from the heat and adjust the seasoning as needed.Preheat the oven to 350 F/ 180 C/ 170 fan/ gas mark 4.
Make the white sauce
Make roux: in a saucepan melt the butter, add the flour and whisk until a smooth mixture forms.
Make sauce: Gradually start adding the milk whisking all the time until the mixture thickens and starts bubbling up (you may not need to add all the milk). Remove from the heat, season to taste and set aside for 5 minutes.
Assemble and bake the lasagna
Lasagne noodles: lightly grease the bottom of a 20/30 cm (8.5/11.5'') dish and arrange 3 lasagne sheets in a single layer.
Add filling: cover with half of the filling mixture and smooth out.
Add bechamel: spread about 40 % of the bechamel sauce over the top. Cover with 3 more lasagne sheets and add the remaining filling mixture. Even out then cover with the 3 remaining lasagne sheets.
Finish off: pour the rest of the bechamel sauce over the top of the lasagna and scatter the cheese.
Bake: bake in the centre of the oven for 45-50 minutes until nicely browned. If after 35-40 minutes the top is still pale broil for the final few minutes (increase the heat to 420 C and cook in the upper part of the oven).
Rest: remove from the oven, set aside for 10-15 minutes then serve.
Notes
*You do not have to precook dried lasagne sheets.
Use ground turkey with approx. 7% of fat (so use lean but not extra lean meat). This recipe will also work with beef or chicken.
Ensure the filling is well seasoned before assembling the recipe (the lasagne noodles will absorb some of the flavour as they cook). It is important to also season the white sauce.
To save time make the white sauce as the filling mixture is cooking.
The bechamel sauce should be quite thick so it can form a creamy layer (you may not need to use all the milk).
Reserve approx. 60 % of the white sauce to pour over the top of the lasagna.
Rest for 10-15 minutes before serving.
Best served hot.
Refrigerate leftovers, covered, for up to 3 days. Reheat individual portions in the microwave.
It's best to freeze turkey lasagna uncooked, wrapped tightly with plastic wrap or foil, for up to 3 months. Bake from frozen for about 90 minutes (or until fully cooked), covering loosely if the top starts to brown too quickly.