Spanish caviar Arrives In France

I AM at the celebrated restaurant Mugaritz in the wilds of northern Spain and chef Andoni Aduriz is playing tricks with our palates.

I'm here with a friend and we're waiting to be called to our table. Out come four grey, perfect ovoids looking like pigeon's eggs and nesting on hot pebbles in a white napkin-lined bowl. We are encouraged to dip them into a garlicky mayonnaise and eat them, "shell and all". It is not until we bite into them that we get the joke. They are perfectly cooked tubers dusted in clay. Yup. Potatoes in mud.

Food with a sense of humour? Obviously things are not going to be what they seem at Mugaritz. We have a reservation for 1.30pm, the usual time for Spaniards to eat lunch, but driving north from San Sebastian and having allowed ourselves an extra hour to find this remote place, we arrive early. The restaurant is not yet open, so we explore the herb garden in the autumnal mist and drizzle. Then, taking pity on us, staff usher us into the detached bar, more of a summer house, across the courtyard from the restaurant.