Clogged regulator or burner?

Yesterday I could not get my Banjo Burner to properly heat. The gas output was really low and inefficient for brewing thus I brewed indoors. Anyhow, my propane tank was full and I even tried another one to eliminate that possibility.
What should I clean/take apart first? And how?

What was the temperature where you were brewing? In very cold weather the propane doesn't evaporate in the tank as well, so there is reduced gas available. Putting the tank in a tub of warm water might help.

It had been upper 20's overnight and mid 30-low40's around brew time. I brought tank and burner inside, used a heating pad to try and warm the regulator on the burner and ambient warmth to warm the tank and nothing helped.

Any ideas or you think it was cold enough to restrict flow? I always imagined temp would have to be in teens to cause flow issues. Just my assumption as I live in MS and low temps are rare

I don't know, but here in WV I can get frost to form on a propane tank when it's in the 30's. The vapor pressure is reduced sufficiently that I get reduced flow through a 30 psi regulator, but not through the 20 psi regulator on my gas grill. Some research on propane vapor pressure might help, it looks as if the pressure goes below 30 psig when the propane's temperature drops to slightly less than 10 deg. F.

Your regulator could be stuck. I've had this happen to me once. I fixed if by turning off the gas on my propane tank and then disconnecting the regulator. It usually happens to me in the winter time when I turn on my propane tank too fast.

I disconnected and reconnected the tank and regulator/burner probably 10+ times.

Messed around with it this morning, disconnected the hose/regulator from the burner, sprayed compressed air, reconnected. Same problem! So I then turned the regulator's built in "gas control valve" all the way off while the burner was lit. I slowly opened that valve and re-lit the burner. As I opened the valve more, the gas flow seemed normal and now all is back to normal! Strange?