Heat your grill to its highest setting. Cut the pepper in half and scoop out the seeds. Cut the tomatoes into quarters. Peel and thickly slice the red onions. Place the veg onto a foil-lined baking tray. Drop on the garlic cloves.
Slide the tray under the grill and grill for 10-15 mins till the veg is softened and slightly charred. Remove from the grill and leave to cool.
While the veg is grilling, remove the leaves from the cauliflower. Chop the cauliflower into bite-sized chunks. Bring a pan of water to the boil. Drop in the cauliflower and cook for 5 mins. Drain and set to one side to dry.
Heat a frying pan. When hot, tip in the cashews. Toast for 2-3 mins till golden and nutty smelling. Tip into a bowl.
Peel the blackened skin from the pepper. Finely chop the flesh. Finely chop the tomatoes. Squeeze the garlic from their skins. They wont be completely soft, but will have lost some of their raw taste. Finely chop them. Finely chop the parsley stalks, setting the leaves aside. Finely chop the cashews and set half aside. Mix together. Alternatively whiz everything in a food processor.
Coarsely grate the cheddar. Mix half of it with the crème fraîche. Pour the cheesy crème fraîche into the pan you used to toast the cashews. Swirl through half of the pepper and tomato mix. Bring to a gentle simmer, stirring. Taste and season.
When the sauce is hot, drop in the blanched cauliflower. Stir to coat it in the sauce. Spoon over the remaining pepper sauce. Then sprinkle over the breadcrumbs. Scatter over the remaining cheese. Slide the pan under the grill for 3-5 mins till the cheese is melted and bubbling. If your pan isn't ovenproof, tip everything into an oven proof dish.
Remove the pan from the grill. Scatter over the remaining cashews. Whisk 1 tbsp red wine vinegar with 1 tbsp olive oil. Toss through the torn lettuce leaves and serve with spoonfuls of the cheesy cauliflower, topped with parsley leaves.