In a small sauce pot, on medium heat, melt butter, next add flour to create a Roux. Roux: See definition in the article above. Once combine cook for a minute to two. Making sure to cook out the flour and taking the Roux to the Blond Stage. Making sure the Roux does not take on any color. Next, add in one cup of stock, slowly, stirring the entire time. Keep stirring and the sauce will start to thicken, and quickly. This is the time you add the other 1/2 Cup of Stock. I like to have additional stock just encase the sauce needs to be thinned out some. Once the sauce is at the correct viscosity for your application/use you're done. You can always thicken the sauce further by cooking additional over medium/low heat. The Veloute can be flavor any way you like. At this point, you'd add in your flavoring ingredients like tomato paste. You can do this over very low heat.