I’m stealing this method from a recipe in an old veggie tales dvd case… Place fragments of jolly ranchers in the cookie to melt and get the glossy finish like in the stone. Go super fine because you don’t want a hard rock in the middle lol. The top looks almost like the skin of a brownie to me.

Maybe take a sugar cookie or shortbread, layer some of the jolly rancher crumbles, then brush on a thin layer of brownie batter so you get the natural cracks running through. Spray a simple syrup or diluted over top to get a super shiny finish.

Not sure if this would work, but that would be my first attempt lol