Preheat the oven to 180°C fan (350°F).

In a small saucepan, heat the butter and cream over a medium heat until the butter has fully melted. Pick the thyme leaves and add to the pan, reserving some for garnish. Set aside but keep warm.

In a food processor (or using a mandolin) finely slice the onions, potatoes, swede and carrot. You can, of course, slice these by hand, but it is important to keep them all the same thickness. If using a food processor, you may need to halve the potatoes and cut the swede into quarters.

Grease a 13 x 20cm (5 x 8in) tin (or similar) with butter. I like to arrange the veg standing up in the tray so you have a crispy top and lovely soft steamed veg below. To do this grab a handful of the veg and arrange roughly upright along the length of the dish. Continue with more handfuls of veg, arranging them so they fit snugly. It will look rough and rustic but don’t worry too much about this.

Add the stock and salt into the warm herby cream and pour over the veg, making sure to cover everything. Sprinkle over the extra thyme and dot over small cubes of the butter. Cover with foil and bake for 40 minutes. Remove the cover and return to the oven for a further 30 minutes, or until the veg is completely soft and the top is golden brown. You can cover again if it browns too quickly.