Grate all ingredients with a box grater (food processor not recommended as the texture is different).
Squeeze out the water from the grated vegetables through a cheese cloth or the like.
Using a flat frypan or crepe pan, heat up some olive oil and then place the grated vegetables in an equal layer on top. Flatten down with a spatula or plate. After browning for a minute or two, flip the rosti to the other side. I find the easiest way to do this is by using a plate to flip onto and then putting back into the pan. Cook until golden on both sides.
Depending on how you like it, I will often pop this in the oven for 10-15 minutes while I prepare other breakfast foods, on 180 Celsius fan forced, this cooks the rosti through and gives a crisper finish.
Serve with a dollop of vegan sour cream or aoili and some fresh dill.

1 large carrot
1 large potato
1 large beetroot
1 small onion
Olive oil