In a large pot, place carrots and potatoes with plenty of water. Bring to a boil, and cook potatoes and carrots until easily pierced with a fork, about 30 minutes. Cook three hard boiled eggs.
Peel potatoes, carrots and eggs (I use the back of a sharp paring knife to peel the potatoes and carrots). Chop finely.
Combine in a large bowl with onions, pickles, peas and dressing ingredients. Mix until well combined – eggs will break a little, and that's OK – they will help flavour the sauce.
Taste and correct seasonings. Let sit in the fridge for at least a couple of hours, preferably overnight.
Serve with a little bit of fresh dill on the side.
