Bob's Red Mill sells vital gluten in many stores. You can add this to your AP flour.

It's also possible to order bread flour and high gluten flour directly from the King Arthur website. They're always running specials which does help to offset the freight. You can also buy some nifty tools from them too.

cowgirlculture, please send me a message via my profile, with your address, and I'll send you some gluten. A little goes a long way, and it should make a difference. (I have a great source of fresh, very high quality bread flour locally, but I always keep gluten on hand for when I run out of bread flour, and am using AP flour instead.) ;o)

Thanks, all they have is Gold Medal unbreached - it will have to do until I can order the bread flour. I appreciate the advice!

Bread flour usually has about 14% protein, whereas AP flour has about 10-12% protein. What this means is you get more gluten formation from the bread flour. The King Arthur unbleached AP flour and the Hodgson Mill unbleached AP are closer to 12% protein so if either is available I'd go for one of them. You should get acceptable results from unbleached Gold Medal which is about 10.5%.

King Arthur unbleached all-purpose flour is very close.

It's too bad your grocer doesn't stock bread flour. It is common where I am even at the chain grocers. You will just have to use all purpose flour and you will get decent results. Try to use one with a high protein % like King Arthur, then Gold Medal unbleached flour. A real substitiute would be to use all purpose, substituting one Tbsp of gluten flour for one Tbsp of the AP flour