Sauté chopped shallot in olive oil until translucent, add sliced mushrooms, sweat briefly and deglaze with white wine and a dash of vinegar. Fill up with the vegetable stock, let it reduce and then strain. Then blend the hot stock and add the soaked gelatine. Boil the vegetable stock in salted water until soft, quench and cool. Line a terrine mold with plastic wrap, then layer or fill with the vegetable stock and vegetables.
Chill in the refrigerator for about 5 hours.
Peel, core and dice the tomatoes. Sauté two-thirds of the diced tomatoes in hot olive oil and reduce to a puree. Season with salt, pepper, sherry vinegar and basil oil.
When cool, add the remaining diced tomatoes and basil leaves. Allow the compote to cool.
Serve with the vegetable terrine.