First of all, pour cold water into your large bowl, add your fresh lemon juice and mix it together.
Take your celeriac and remove the stalks and leaves. These can be used in other dishes.
Peel the celeriac with your vegetable peeler and use your sharp knife to cut it up into rough 2-3 centimetre chunks, adding the chunks to the lemon water as you go.
Now add your olive oil and onion to the pan and saute gently for a few minutes on a medium to low heat until they start to go translucent.
Add your potato and carrot to the onions and oil and mix together.
Now, with a slotted spoon, remove your celeriac chunks from the lemon water and add them to the pan.
Stir everything together and leave them to gently heat through for 5 minutes.
Now add your orange juice and stir that in.
Turn the heat to high and add enough of the lemon water until the liquid just covers your celeriac and other vegetables.
Give everything a stir, bring to the boil and then cover with a lid before returning the heat to low.
Leave your celeriac to simmer and braise for 30 minutes.
Now check that your vegetables are soft. Don't let them get too soft that they start to go mushy.
When your vegetables have softened, remove from the heat and pour everything into a shallow serving bowl to cool to room temperature.
Sprinkle your chopped dill over the top before serving.