Boil the potatoes, unpeeled, until fully cooked but don't let them cook until the peel starts to split (this means they are overcooked). Drain as soon as they are cooked (check with a fork) and set aside to cool completely before making the salad.
While the potatoes are boiling prepare the beets. Place the beets on top of a baking sheet and roast in a preheated oven at 400 F/ 200 C/ gas mark 6 for about 40-45 minutes or until moderately tender (check with a fork). Remove from the oven and set aside to cool completely.
Peel and dice the potatoes and beets, then core and finely dice the apple. Place in a mixing bowl and add the rest of the ingredients.
Stir thoroughly, adjust the seasoning if needed and refrigerate for 30 minutes (if possible) before serving.
You can cook both the beets as well as the potatoes in advance and once cooled refrigerate (overnight), covered, unpeeled, until you are ready to make the salad. Peel and chop when you are ready to assemble the recipe.
*Use waxy potatoes such as baby or new potatoes, red potatoes, fingerling or Alexandra potatoes.
**Dill pickles/pickled gherkins: These can be marinated either in vinegar (these are sold in all supermarkets and this is also the type I used) or traditional Polish dill pickles in natural brine (sold in Polish stores).
I recommend using a sweet rather than sour apple variety (Pink Lady is a good choice).
Prepare the apple just before adding into the salad as it's prone to discoloration. You can but don't need to peel it.
Tweak the ingredients to your taste: for example use more mustard, lemon juice etc.
Best served the day it was made. You can keep this salad refrigerated for up to 6 hours.
If possible chill this potato beet salad for 30 minutes before serving.
Not suitable for freezing.
I recommend wearing rubber gloves when handling the beetroot.
You can use fresh dill in addition to or instead of the parsley (use 1 tablespoon or to taste).
Use natural or Greek yogurt, Skyr or fromage frais/fromage blanc.
I used olive oil but vegetable oil will work equally well.
Preparation time includes cooking and cooling the beetroot and potatoes.