Classic Vegetable Stock

Coarsely grate carrots, celeriac, and parsley root. Quarter the leek lengthwise and cut into pieces about 0.5 cm thick. Finely dice onions, mushrooms, and tomatoes. Roughly chop the flat-leaf parsley.

Heat the sunflower oil in a large pot over high heat. Add the grated root vegetables (carrots, celeriac, parsley root) and sauté for about 2 minutes, stirring frequently.

Reduce heat to medium. Add leeks, onions, mushrooms, and tomatoes and sauté for another 8 minutes, stirring, until the vegetables soften and release their aroma.