Preparation

• 1
  Preheat the oven to 180 degrees, 160 degrees fan oven.
• 2
  To make the white sauce, cut 40g of butter into small pieces and melt in a saucepan. Stir in the plain flour to make a paste and then gradually add and stir in the milk to make a thick sauce. Season with salt and black pepper and a grating of nutmeg.
• 3
  Peel and finely slice the onions, saute gently for 5 minutes in a tablespoon of olive oil to soften, and then tip into a small bowl. Wipe and slice the mushrooms then saute in the same pan in a little olive oil for 2-3 minutes.
• 4
  Meanwhile, cook the petit pois in boiling water.
• 5
  Peel and slice the potatoes very thinly. Shred the cooked turkey.
• 6
  In a medium sized deep oven dish, lay a thin layer of potato. Spoon on half of the white sauce, half of the onions, peas and mushrooms then half of the shredded turkey.
• 7
  Add another thin layer of potato then the remaining layers of turkey, onions, peas and mushrooms, topped with the rest of the white sauce.
• 8
  Lay the remaining potato slices, overlapping, on top of the sauce. Peel and crush the garlic then mash with 20g of softened butter. Dot the garlic butter all over the potato topping and add a sprinkling of black pepper.
• 9
  Bake in the preheated oven for 50 minutes, then raise the heat to 200 degrees, 180 fan oven, and cook for a further 25-30 minutes or until the potatoes are golden brown with crispy edges.