Wash the potatoes, brush them off and steam them with a little water.
In the meantime, wash the herbs, roughly chop them, puree them with the olive oil and 2–3 tablespoons of vegetable stock, season with sea salt.
Peel and mash the potatoes or press them through a potato press. Stir a third of the vegetable stock and the herb pesto into the mashed potatoes. Gradually pour in enough stock until the puree has a pleasantly creamy consistency.