This is the same as above only instead of milk you are adding stock. This could be chicken, fish, beef, veal or even vegetable. Once again: fat + starch + liquid = a thickened sauce base.
A light brown sauce or Veloute is made when the stock is light in colour and an Espagnole sauce is one where the stock is darker due to roasting the bones before making the stock. As well the Roux (fat + starch paste) has been cooked a little longer to a golden brown colour.
Make Roux as in white sauce
Add any stock on hand gradually until thickened
Add flavourings of your choice such as soy sauce, hot sauce, peppercorns, or onion powder.