Cut the aubergines, zucchinis, and onion into thick slices.
Cut the bell peppers into half and along with the sweet corn and the unpeeled garlic cloves.
Sprinkle lightly with oil and salt. Place the vegetables on an oiled grill or an oven safe tray or pan. See note 2.
Separate the cauliflower into florets and place in an oven proof tray along with the garlic and the long beans.
Place the tray into the oven along with the grill with vegetables and grill over medium heat (about 220℃/428℉) until the vegetables are soft. The veggies should not be mushy and the cauliflower should still have a bite to it. See note 3.
Grill until the vegetables are soft but not mushy. The cauliflower and the long beans should still have a bite to them.
Leave the vegetables to cool.
Toast the pistachios in a pan and leave to cool. Then using a coffee grinder or processor, blitz the nuts.
In a mortar or a processor grind the basil with the pistachios and the roasted garlic (remove the peel), adding salt and oil in bits until a somewhat uniform but not completely smooth paste is formed.
Remove the kernels from the sweet corn by running a knife close to the cob through from top to bottom.
Chop the rest of the vegetables, add the pesto dressing, and mix well making sure to adjust for salt and black pepper.
Serve at room temperature.