Turnip, potato & mustard gratin

• milk↗450ml ml
• turnips6

  thickly sliced

• large potatoes↗6

  thickly sliced

• butter↗

  for greasing

• garlic clove↗1

  halved

• double cream↗350ml ml
• Dijon mustard↗3 tbsp

Step-by-step instructions

1. 1

   Fill a saucepan with 500ml water, the milk, a good pinch of salt and a grinding of black pepper, then bring to the boil. Add the turnips and potatoes and cook for 2 mins. Strain, drain well and pat dry.

2. 2

   Heat oven to 180C/160C fan/gas 4. Butter a baking dish and rub the sides with garlic to just add a hint of flavour. Mix the cream and mustard in a large bowl, add the potatoes and turnip, mix until well coated and season really well. Layer into the baking dish, flattening the top level. Can be assembled and chilled a day ahead.

3. 3

   Bake for 30-40 mins or until golden brown and the turnip and potato are cooked through – check with the point of a sharp knife.