Gather your mis en place; get together all of the equipment needed for the recipe and gather your ingredients.

Measure out the butter, flour, salt, milk, mustard powder and cream of tartar.

Grate the cheese and cut the green onion or chives.

Separate the eggs.

Preheat the oven to 375° F. Melt the butter in a medium pot over low heat. Stir in flour, salt and pepper, mustard powder and hot sauce. Cook, stirring constantly, until the paste is smooth and bubbly.

Slowly stir in the milk in batches. Continue stirring until mixture boils and is smooth and thickened set aside.

Beat yolks well and add to the cooled but still warm sauce mixture. Mix well.

Add finely chopped chives or onion and cheese, stirring into white sauce until blended. Set sauce aside to cool slightly.

Beat egg whites and cream of tartar in a large bowl, until stiff .Fold some of the egg whites into sauce to make it lighter, then gently but thoroughly A technique used to gently mix two ingredients together to create a light fluffy consistency. Start by scooping around the outside of the bowl and cutting through the centre. Turn the bowl and repeat the process.fold the sauce into the remaining egg whites.

Carefully pour into a 4‑cup or 1 litre soufflé or casserole dish (can use a glass pie plate).

Bake in a preheated 375° F (190° C) oven until puffed and lightly browned, 20 to 25 minutes. Serve immediately.