This is more of a salsa-type thing, I suppose, but you can use it to accompany smoked or pickled fish, cold meats and so on. Otherwise, simply spoon it on some toast as a snack.
You can mix a little crème fraîche or mayonnaise with this at the end to make it creamier, or, depending on your tastes, just leave it clean.
250-300g cooked beetroot (any colour)
1 medium red or white onion, peeled, halved and finely chopped
2-3tbsp capers, rinsed and chopped
1tbsp Tewkesbury mustard or Dijon, mixed with some horseradish
1-2tbsp rapeseed oil
Salt and freshly ground black pepper
Peel the beetroot and finely chop them, then mix all of the ingredients together and season to taste. You can add more capers or mustard if you wish.