Ingredients:
50 % butter, 50 % flour, (No quantities are given. This binding is used in different cases. Check the corresponding recipes)
Method
Slowly melt the butter in a skillet...
...without browning it.
Add the flour (the weight of flour is always identical to the weight of butter).
Mix the butter and flour, stirring with a wooden spoon. Stir all over the pot...
...to prevent browning and the formation of lumps. The roux must be perfectly smooth and white. Cook for 4 to 5 minutes. When finished, set aside to cool until you need it.
...