Preheat the oven to 180C/Gas4; put the heads of garlic on a large sheet of foil set in a small roasting tin; drizzle with half the olive oil and add about 4 tablespoons of water; seal the parcel (leave room around the garlic) and bake for about 30 minutes until the garlic is completely tender
Meanwhile, chop the sweet potatoes into chunks, put in a small roasting tin and drizzle with the remaining olive oil; bake with the garlic until tender
Remove the garlic from the oven and set aside until cool enough to handle; put the sweet potato into a food processor with plenty of seasoning; squeeze the garlic from each clove and puree with the sweet potato; turn the oven up to 190C/Gas5
Melt the butter in a saucepan and add the flour; stir over a low heat for a minute or so until the butter and flour come together and turn pale-biscuit colour; take the pan off the heat and gradually add the milk, stirring well after each addition. Put the pan back on the hob and heat, stirring all the time, until the mixture is almost boiling and very thick; stir in half the cheese and cook over a low heat until the cheese melts; add the sweet potato and garlic puree, cool a little and then add the egg yolks; season really well; whisk the egg whites until they stand in medium peaks; loosen the sauce with a couple of very large tablespoons of the egg whites, then fold in the rest
Divide the mixture between the ramekins; set the ramekins in a roasting tin and add enough water to come a third of the way up the sides; put in the oven and cook for 25-30 minutes or until the soufflés are golden and set; take them out of the oven and allow to sink and cool completely; turn the oven off
To serve preheat the oven to 220C/Gas7. Turn the soufflés out on to baking trays; spoon over the cream and sprinkle the remaining cheese; make sure that the tops of the soufflés are well covered in cream; bake for 10 minutes; transfer to serving plates, scatter with a little parsley and serve immediately
Servings 0