How can I repair a shattered clay pot lid?
White glue (Polyvinyl acetate) will fail in the oven.
So will regular superglue (cyanoacrylates).

However, there are specialty Cyanoacrylate Adhesives that are good up to 250°C (480°F).  Look around, you may be able to find something at a reasonable price.

Epoxies, liquid nails and the like do not seem to me a safe choice to use near food.