There's a clear way of dealing with this better:
Import the clock from the rules of chess. Every contestant gets ten hours to use as they wish. If you reach the final round with no time left you'd better hope John and Greg like their fish raw.
Once you've done this, of course, you can add in something else to make it even more fun - a bidding system. At the start of each round every cook gets to bid downwards for how quickly they can make an amazing plate of food. "I can sous vide a chicken and then pan fry it in slow cooked fig leaves in 90 minutes." "Well I can smoke a whole elk in 70 minutes".
And finally, we ratchet up the challenge by reducing the number of ingredients and tools they have to work with. The first episode gives access to a market and fully equipped kitchen, and then one ingredient and one tool is removed each episode until all they have is a single chicken breast and a blowtorch to cook it with.
I await the adoption of my clearly superior rules in the next season.
Original post on Dreamwidth - there are comments there.