After watching a redstone-tour with a functioning grill I decided to make one myself without any look at others designs. This is all from off the top of my head and I'm not sure if anyone else has used hopper minecarts for theirs but oh well.

How it works is you flick the gas-lever on the top which activates the hopper minecart to take any cooked meat out of the furnace. After flicking the lever you place whatever raw food you want into the hopper and wait a moment. Once it is done cooking it is picked up by the hopper minecart and placed in an elaborate system of hopper elevators that transports the newly cooked produce back up to the surface as your sustenance.

It took around an hour to come up with the design and I am fairly proud with how anti-buggy it is if you use it right.

Thankyou for checking this out, all feedback is appreciated, even if it is a series of curse-words.
Feel free to comment or give this a diamond. I don't expect much since this is just something small.
Thanks again. :)