Celeriac and walnut gratin

I found the recipe for celeriac and walnut gratin at BBC Good Food but adapted it a bit as blue cheese is not my favourite (cannot look at the mold and eat it). I also grated the celeriac and loved how it turned out.

Celeriac and walnut gratin
adapted from BBC Good Food
one 900 gr unpeeled celeriac
or
one 600 gr peeled celeriac
3 dl vegetable stock
150 gr chopped walnuts
6 tsp walnut oil

Coarsely grate the celeriac, put in a baking dish (mine holds 1,3 liters) and pour over the stock. Bake for 45 minutes in preheated oven (180 C). Sprinkle with walnuts and bake until walnuts get a bit of colour, around 15 minutes. Take out of the oven, cut in squares, put on a plate and drizzle some walnut oil over.