All party spreads need at least one kind of pickles, and these can be whipped up in a flash. By cutting the mushrooms nice and thick, you keep them in toothsome chunks that sit pretty on a tear of fresh pita. Make this recipe the morning of party day, or even a couple of days before. The Provençal twist, with red bell pepper, fresh thyme, coriander seeds and white wine vinegar, brings a ray of French sunshine into the mix.