Slice onions in half, peel, save the trim for later, then slice thinly not too thin though.

Add to a frying pan, a knob of butter, the onions, a good amount of salt and a shot of water. This shot of water is a key ingredient to speed up the caramelisation process of the onions.

Cook in frying pan over a high heat for a few minutes to get them started, then reduce the heat and continue to cook (see video)

Next, grab a saucepan, add 750 ml of water, 2 chicken stock cubes and all the onion trim from earlier and add the thyme stalks to the saucepan as well.

Peel the potatoes, then slice them on a mandolin, I go for around the width of a poker chip. (see video)

Once the onions are ready, remove half the onions and set aside, spread the rest out so they cover the base.

Add a little stock, this will steam the potatoes from underneath and help them to cook evenly.

1st layer of potatoes, thyme, salt, a little pepper, stock.

2nd layer potatoes thyme salt pepper.

3rd layer potatoes this will have the other half of the onions thyme salt pepper

4th layer potatoes thyme salt pepper

5th and final layer, this is the layer to make pretty, so I’m taking a little extra time to tuck in the slices, and make it look nice, give it a press, some stock should rise to the surface, then I’m adding a bit more.

Into the oven at 160-170°C, no higher than 180°C, otherwise the top will be cooked before the centre.

After about 30 minutes, give the potatoes a first press, then press them every 15 minutes or so and rotate the pan to get them to cook evenly. They'll be ready after just over 1 hour, you can check this by piercing a knife into the middle, if there's no resistance they are ready.