Before starting this Sauce Suprême recipe, make sure you have organised all the necessary ingredients.
In a saucepan, melt 90 grams of butter to make a blond roux...
... then add the flour, making sure it does not brown.
Combine gently with a whisk.
Add the cold chicken stock to the hot blond roux. Otherwise, add hot chicken stock to the blond roux if it is cold. Working with different temperatures is essential to avoid lumps. Combine with a whisk.
Bring to a boil, then cook for 15 minutes.
Add the crème fraîche and reduce for 15 minutes, whisking at regular intervals.
Pass the sauce through a fine sieve or chinois, using a rubber spatula.
Season to taste. Return the pan on the stove and bring to a boil.
Add the remaining cold butter (40 grams) in one go. This will give the sauce a creamier consistency. Whisk until homogeneous.