Bring a large pot of water to the boil and add the quartered orange, the cloves, the sea salt, bouillon and the peeled celeriac. Cover with a lid and boil the celeriac for 30 minutes.
To make the glaze, in a small bowl, stir together the remaining ingredients with 3-4 tablespoons of the celeriac cooking broth.
Once the celeriac has been boiled for 30 minutes, carefully remove from the broth and transfer to a roasting tin.
Brush the celeriac with some of the glaze then place in the oven to roast for a further 30 minutes, removing from the oven to re-glaze every ten minutes.
Remove from the oven and either slice and serve while hot or leave to cool and slice thinly for cold-cuts.
It's insanely delicious and makes such wonderful cold cuts, you'll be serving it with crackers and vegan cheese for days after!