Ingredients
1 tbsp olive oil
1 onion, finely chopped
2 garlic cloves, minced or very finely chopped
400g cooked chicken, sliced
250g mascarpone 
1 chicken stock pot
1 jar of pesto (around 170g)
400g spicy tomato pasta sauce
250g fresh Lasagne sheets
Freshly ground black pepper

Ingredients for the Bechemel
50g butter
50g flour
425ml milk
150g strong cheddar

Method
Over a medium high heat, put 1 tbsp of oil into a frying pan and add the onions cook until soft and transluscent, around 5-7 minutes. Once soft and without any colour, add the garlic and cook for a further minute.  Add the chicken and stir.  To the chicken add the mascarpone, the stock pot and the pesto and cook until everything melts.  Add freshly ground black pepper and check the seasoning, adjusting if necessary.

While the chicken is cooking, get your pasta sheets and cheese sauce ready.

Bring a large pan of water to the boil.

To make your béchamel add the butter and flour and vigorously stir until the butter has melted and for another minute.  Slowly add your milk a bit at a time, stirring to ensure there are no lumps as you go.  Leave the sauce to cook on a low heat for 5 minutes.  Turn off the heat, add the cheese and stir until melted.  Check the seasoning and adjust where necessary.  Preheat your oven to 180c.

When the water is boiling you want to turn off the heat and add your pasta sheets one at a time.  You want to leave them in the hot water for 2 minutes no more.  Carefully take out your sheets and lay on your board making sure they do not overlap.  Put a sheet of greaseproof paper or cling film if you need to, to keep them separate.

In a large square dish add some spicy tomato sauce and top with pasta sheets.  My dish takes 1 whole sheet and a quarter sheet to cover my dish so I just cut a sheet into 4 but just adapt to fit your dish.  Top with spicy tomato sauce then top with some of the chicken. I usually get 5 chicken layers and 5 pasta layers so I try to eye how much sauce I can use per layer.  Just keep going pasta, tomato, chicken, pasta, tomato chicken until everything is used up.  I end on a pasta sheet and I top with cheese sauce.  Bake for 30-45 minutes until golden brown.  Cut into 9 portions. Serve with garlic bread.