50 % butter, 50 % flour, (No quantities are given. This binding is used in different cases. Check the corresponding recipes)
Slowly melt the butter in a skillet... ...without browning it. Add the sifted 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. ...
To pour a substance (flour) through a sieve in order to remove lumps.