Veloute Sauce is another of the French "mother sauces", using stock instead of milk. This is from Mastering the Art of French Cooking, by Julia Child and Simone Beck.
--A NOTE ON EQUIPMENT: The recipe actually calls for a heavy-bottomed, 6-cup enameled, stainless steel, lined copper, porcelain, or pyrex saucepan and the use of a wire whisk for mixing. If you use anything with a non-stick coating, use a nylon whisk instead. A thin-bottomed pan is a poor heat conductor and may cause the sauce to scorch. Aluminum can discolor a white sauce.
--2 tbsp Butter
--2 tbsp Flour
--2 cups Veal, Chicken or Fish Stock (not made from bones that were roasted), brought to a boil
In saucepan, melt the butter over low heat. Blend in the flour, and cook slowly, stirring, until the butter and flour froth together for 2 minutes without coloring. This is now a white roux. Remove the roux from the heat. As soon as the roux has stopped bubbling, pour in all of the hot (nearly-boiling) stock at once. Immediately beat vigorously with a whisk to blend liquid and roux, gathering in all bits of roux from the inside edges of the pan. Set saucepan over moderately high heat and whisk until the sauce comes to the boil. Boil for 1 minute, stirring. Remove from heat, and beat in salt and pepper to taste. Sauce is now ready for final flavorings or additions as you wish.
If not used immediately, clean sauce off inside edges of pan with a
rubber scraper. To prevent a skin from forming on its surface, float a thin
film of stock or melted butter on top. Set aside uncovered, keep it
hot over simmering water, refrigerate, or freeze it.