Pan sauce without meat I like pan sauces with my chicken or beef, but prefer the meat cooked over cast iron.  Pan sauces apparently don't work well in cast iron, and should be done in a stainless steel saute pan.

How can I make a nice pan sauce if the meat has been cooked in a different pan?

The best I can think of is to save a small amount of the meat to be cooked into fond to start the sauce off.  Will that work?
I think de-glazing the cast iron pan would be a good solution.

After the meat is cooked, remove it from the cast iron pan, and with the pan still on the heat, add a small amount of liquid. Just about enough to cover the bottom of the pan 1/4 inch. Then scrape the bottom with wooden spoon to get up all that goodness stuck to the bottom.
Add this to your sauce to get the meat flavor into it.

Liquids you can use include: wine, stock, water, beer, probably a lot of other stuff. And the type of liquid to use would depend on the dish and personal preference.