Velouté sauce is actually just a white sauce that is stock based and thickened with a white roux. Velouté is a form of the French adjective velour, which means “velvet.
It's made by heating 2 T of butter (clarified is best) with 2 T flour to form the roux. Then you whisk in 6 cups of chicken stock and let it simmer for 30 minutes until reduced by about a third.
Strain until velvety and set aside until needed. Serve over chicken, fish, veal or rice.