Boil, peel and slice the potatoes. Halve the tomatoes, cut the spring onions into rings and wash the thyme.
Roughly chop the walnuts and roast them in a pan without fat. But not for too long, otherwise they can become bitter. Then take it out of the pan.
Heat the butter and fry the potatoes in it for about 10 minutes. Add the tomatoes, spring onions and thyme to the potatoes and fry everything together for another three minutes. Season with salt and pepper and sprinkle with the walnuts.