Preheat the oven to 220°C / 425°F / gas mark 7
Measure all the ingredients together into a bowl with 75g of the cheddar cheese. Season and mix well together. Turn into a shallow ovenproof dish and top with the remaining cheese.
Slightly crush the crisps and mix with the remaining cheese. Sprinkle over the top followed by a dusting of paprika
Put in the preheated oven or the roasting oven with the grid shelf on the top or second runners and cook for 10-15 minutes until hot. Careful not to cook it for too long as otherwise the sauce will separate. Serve immediately.