This is a recipe from Norman Van Aken that I've been lugging around for years. I did alter it a smidge - whisking in the sour cream vs. adding it to the blender - I think it has a better texture. I keep a batch of this sauce at all times for meat, veggies, potatoes... It's from his cookbook New World Kitchen but I ripped it out of a magazine. It's very simple & keeps for at least 2 weeks.