I did some in a cast iron chicken fryer in the home oven one time, they were light beans I wanted dark for an essspprreessooo experimint.
I just set the oven at 350 and stirred them every few minutes. I did boil some hot water in the skillet first to get rid of some of the oils.
Civil War folks and earlier period do it all the time over a fire, just don't scorch them and roast them as even as possible.
BTW the essssppreessooo experimint was some what of a sucess, used Celebes beans, but can only get them light roasted. I don't think my nephew and my brother-in-law got to sleep at all that night, heard about it from my sister-in-law.
Celebes beans have the highest caffeine content of any coffee bean. Celebes is an island in the East Indies.
It is a pain in the butt though, thank you to the Arbuckles Brothers and the other coffee roasters of the post-Cival War era.