Avocado with smoky tomato-tamarind relish

1. Preheat the grill to high. Lay the halved tomatoes out in a baking tray, cut-sides up. Add 2 whole shallots, still in their skins, the unpeeled garlic cloves and the whole chilli. Grill for 10 minutes, leaving the tomatoes undisturbed, but turning the other vegetables with tongs every 3 minutes or so, until everything is beginning to char around the edges. Allow to cool for 15 minutes. 

2. Once cool enough to handle, slice the root ends from the shallots and garlic cloves and remove their skins; de-stalk the chilli. Put the contents of the tray in a blender or the small bowl of a food processor. Add the tamarind paste, sugar, fish sauce, peanut butter and lime juice. Whizz briefly to form a textured dressing and season. The dressing should be hot, sour, salty and sweet, so add more fish sauce/salt, lime or sugar as needed. 

3. Peel the remaining shallot and slice very finely into rings. Cut the avocado flesh into quarters and pick the leaves from the coriander. Combine the sliced shallot with the watercress, radishes, cucumber and coriander leaves on serving plates, topping with the avocado quarters. Spoon the dressing over and finish with the toasted sesame seeds.