• Put the whole, unpeeled potatoes in cold water, bring to the boil and simmer for 5 minutes.
  • Drain and cool a little.
  • Cook the chicken in a hot non-stick pan until browned all over. You can add a knob of butter if needed but there should be enough fat on the meat to fry it.
  • Scoop out of the pan and set aside, then add the leeks with a knob of butter. cook until softened then add the mushrooms and cook until soft.
  • Sprinkle over the flour and stir well.
  • Gradually add the milk and cream, stirring until you have a sauce.
  • Add back the chicken, season and simmer for 5 minutes.
  • Add the tarragon.
  • Heat the oven to 200C/fan 180C/gas 6.
  • Divide the mixture between 4 heatproof pie dishes.
  • Peel and coarsely grate the potatoes.
  • Toss with a little seasoning then top the pies with the rösti mix.
  • You can drizzle a little extra butter on top if you want them more golden.
  • Bake for 30 minutes until the rösti is cooked and crisp on top. if you dont like tarragon substitute with dill, or thyme & rosemary.