How do I rescue botched gravy?

Thank you everyone! Great suggestions! I ended up re-roux-ing with the flour I had on hand, slowly incorporating the hot gravy, and then simmering it for a while. It worked perfectly!

In such situations, especially when time is of the essence, I cheat by pouring the gravy into a blender & whipping the daylights out of it to make it smooth!

Try using sweet rice flour in future gravies. It's gluten-free, but it'll thicken a gravy like no one's business and it incorporates extremely well while whisking.
http://www.asianfoodgrocer.com/img/prods/panko-flour/10003590-sweet-rice-flour-lg.jpg

I love Wondra!

try taking equal parts soft butter and flour and mix them togehter well (alias beurre manié). re-heat the gravy on the stove top, and start adding in the butter-flour mix a teaspoon at a time until the gravy is re-emulsified and the new flour is cooked. or, you could start with a new roux, adding in the gravy and whisking vigorously to bring the gravy back together.

You could also consider tapioca starch. It thickens quickly and doesn't have a raw flour taste to it. Check out the info at cook's thesaurus on thickeners: http://www.foodsubs.com/Thicken.html

I might try taking a little of the hot gravy out of the pan, put it in a smaller pan and whisking in a small amount of flour until it is well mixed in, then adding more of the old gravy into it continually whisking it. Also beleive in the Wondra advice!

You could try smashing some softened butter with flour and adding that to the mix while warm. Whisking and incorporating it back to gravy.

For future use: Wondra Flour.
Sold in the baking section in a blue canister with a shaker top. It's granulated flour that incorporates to gravies while warm with very little clumping...and my 'go to' for rescuing a separated gravy.

It's also perfect for putting a slight crust on seafood or chicken when you just want a bit of flour for a shallow fry in a just a bit of oil.