Did you try the Inn/Tavern? Usually cooking fires in there. I remember finding a cooking fire but that was in a place where Mobs were, so out in the country.
Edited by Nestor on March 8, 2016 11:26PM
Enjoy the game, life is what you really want to be worried about.
PakKat "Everything was going well, until I died"
Gary Gravestink "I am glad you died, I needed the help"
There's one in the Hew's Mane Tavern in the center of town (on the ground floor, outside section). There's one outside of the Thieves Guild on top of the building to the East. Besides those most houses have one if you don't mind breaking into them.
Edit: Noticed one just South of the Thieves Guild entrance in town too, conveniently just North of the craft stations in Sharper's Alley.