Chicken, squash & pesto lasagne

Name: Chicken, squash & pesto lasagne
Prep time: 20 min
Cook time: 1 h 5 min
Total time: 1 h 25 min
Cuisine: Italian
Ingredients: 2 tbsp olive oil; 2 onions , chopped; 2 garlic cloves , crushed; 4 skinless chicken breasts; 1 tbsp plain flour; 600ml chicken stock; 500g tub mascarpone; 190g jar pesto; bunch basil , leaves picked and chopped, save a few small whole leaves to serve; 1 butternut squash , peeled, deseeded and cut into chunks; good grating of nutmeg; 12 lasagne sheets; 85g parmesan , grated; splash of milk; 50g pine nut