Start this recipe by cooking the lasagna sheets in a pan of boiling hot water to soften then drain. Next, fry the garlic and onion in 2 tbsp. olive oil until soft. Add in the butternut squash and rosemary and fry for 5 minutes to soften before adding in the diced chicken. Cook for a few minutes, season well with salt and pepper and add in the spinach leaves to wilt. Allow to cool down while before you mix in the ricotta and chopped walnuts. Meanwhile, make a white sauce. Melt 2 tbsp. butter in a pan, stir in the gluten free flour and cook for 1 minute. Whisk in the milk , salt, pepper and nutmeg and keep mixing until it begins to thicken. Remove off the heat, stir in the grated cheese and put aside. Lay out the pre cooked lasagna sheets on your worktop and spoon the ricotta filling on one side. Roll up and place into a greased oven dish side by side. Pour over the cheese sauce, sprinkle over the breadcrumbs and bake in the oven at 200°C for 20-25 minutes or until golden brown. Serve decorated with extra spinach leaves.