In a medium saucepan heat vegetable oil and then sauté vegetables until soft.
Add stock, Worcestershire and bay leaf and cook until volume is reduced by one-third, about 25 minutes. (Sauce should be thick and syrupy.)
Strain sauce and return to heat.
Whisk in heavy whipping cream.
Reduce heat to low and slowly blend in butter one cube at a time, adding additional butter only after previously added butter has completely incorporated into the sauce. This process is called "mounting the butter."
Remove from heat and continue to stir.
Season to taste with salt and freshly ground black pepper.
Yield: About 1 1/2 cups
NOTE: The Creole Meuniere Sauce breaks easily so you should either prepare it at the very last. Or if time prohibits then you can prepare it and reserve it covered, on a warm stovetop but off of the direct heat.