Diana Henry’s beetroot and potato gratin

This is absolutely delicious with roast beef or salmon. You can add about 3 tsp of creamed horseradish if you want (just spread it out between the layers). It’s also good with the addition of flaked smoked mackerel, in which case it makes a good main.

Prep 20 mins | Cook 1 hour

6 as a side dish

Ingredients

1kg potatoes, preferably waxy ones
500g cooked beetroot
425ml double cream
140ml sour cream
85ml full fat milk
salt and pepper
3tsp creamed horseradish (optional)

What to do:

  1. Pre-heat the oven to 180C
  2. Peel the potatoes and slice very finely – a mandoline is the best way to do this. Cut the beetroot into fine slices as well – they don’t have to be as thin. You can cut them with a knife.
  3. In a large saucepan, mix together the creams and the milk and bring the liquid to just under the boil. Add the sliced potatoes and cook gently for 5 minutes.
  4. Season really well and spoon ½ the potatoes into a buttered gratin dish. Put a layer of beetroot on top – seasoning as you go, then top with the rest of the potatoes and their cream. Put in the oven for 1 hour, or until the vegetables are completely tender. You may need to cover the top with foil after 45 minutes to stop the top becoming too dark in colour.