Preheat the oven to fan 220°C/gas mark 9, then place 11⁄2 tablespoons of the ghee in a large roasting tray and pop in the oven to heat up.
Meanwhile, dry the beans well in a tea towel to ensure they don’t spit in the hot ghee.
Once the tray is hot, remove from the oven and toss the beans in the melted ghee, along with a good pinch of salt and pepper and the dried herbs, then spread out in a single layer and roast for 15 minutes. Add the rest of ghee and the nuts and bread chunks, toss everything together well and spread out again into a single layer, then pop back in the oven to cook for another 10 minutes.
Remove the tray from the oven and let the roasted bean mixture cool for 10 minutes, if you’ve got time, as it will crisp up more as it cools.
Meanwhile, add the dressing ingredients to the small bowl of a food processor, along with about 4 tablespoons of water, then blitz to combine. Season with salt and pepper and add 1–2 tablespoons of water if the dressing needs thinning down.
Slice off the ends of the lettuces and separate the leaves, then wash and dry really well so that the dressing doesn’t slide off the leaves. Arrange haphazardly on a big serving platter.
Scatter the roasted bean mixture over the leaves, drizzle over half of the dressing and sprinkle with extra grated cheese.