Preheat the oven to 190'C.
Grate the white cheddar and mix it with the Gruyere.
Place the butter into a large saucepan and melt it over a low heat. When the butter is completely melted add the flour and whisk well until the mixture forms a stiff ball and no longer sticks to the pan.
Gradually add the milk whilst whisking all the time and bring the mixture upto the boil. Cook for a few minutes and then remove the pan from the heat. Allow the mixture to cool slightly.
Once cool, add the egg yolks and whisk quickly. Once all of the egg yolks are incorporated, add the two cheeses and the salt and the pepper.
At this stage the mixture will be thick and glossy. Check the seasoning and add more salt or pepper of needed.
Set the mixture aside ready for assembling the souffle.
Using a stand or hand mixer, whisk the egg whites until they turn white in colour and become bubbly. Add the salt at this stage and keep whisking until the egg whites reach stiff peaks. This should take no longer than 90 seconds.
Remove the egg whites from the machine.
Soften the butter.
Brush the ramekins with the butter, brush upwards and this will prevent the souffle from sticking to the sides of the ramekins.
Ensure the ramekins have a good coating of butter.
Place a tablespoon of the souffle base into a large bowl. Whisk well to remove any lumps. Add a small amount of the egg white to the base and whisk well until the mixture is smooth. Now remove the whisk and replace it with a spatula. Fold the mixture together, ensuring the egg whites are fully incorporated into the base.
Fill the ramekins with the souffle mix. Using a pallet knife, scrape the top of the souffle to ensure the tops are flat and smooth. Tap the ramekins on the surface to remove any large air bubbles (large air bubbles will stop the souffle rising evenly).
Bake the souffles in the oven for 8 minutes
Serve straight from the oven.
«Try to use pasteurized egg white for making souffles as they whisk quicker and are more stable.»