That's a tough one. I assume the top is smooth, like our GE Profile (non-halogen) smooth-top cooktop. We both despise it for the difficulty of temperature control and the necessity of continually and obsessively cleaning it. I've investigated induction units, but we'd have to have our granite counter re-cut or more likely replaced, and rework the custom-made cabinets beneath it, so we're stuck. Word to the wise.
Anyway, to insulate your wayward pussycat, I don't see how a metal cover could work, as it would immediately pick up heat from the hot surface; any kind of plastic would presumably melt onto the stovetop.
How about putting an inverted dinner plate on top of the hot burners? It would probably heat up less and more slowly than something metal. It might give your cat a hotfoot, but maybe not a burn.
I'd suggest a water pistol immediately to hand to give your cat a good shot if
you catch her on any kitchen counter, or table for that matter. :o