Preheat oven 400F/200C/gas mark 6. Butter 6 individual ramekin dishes and dust with the parmesan cheese.
Melt the butter or margarine in a saucepan. Add the flour and cook for 2 minutes, stirring. Stir in the milk. bring to a boil, stirring constantly, and simmer until thickened, about 5 minutes. Remove from the heat and let cool about 10 minutes.
Stir in the cheddar cheese, egg yolks, and dill into the sauce. Season with salt and pepper to taste. Transfer to a bowl.
In another bowl, beat the egg whites with a 1/8 tsp salt, until stiff peaks form.
Stir one quarter of the egg whites into the cheese sauce mixture to lighten it. Fold in the remaining egg whites.
Divide the mixture evenly between the prepared ramekin dishes. Bake until the souffles are puffed and golden, 15 - 20 minutes. Serve immediately.