if that only happens with big cookies, I suppose it's similar to a masonry. the edge dries faster than the inside. To avoid this, water is sprayed on again and again.
Maybe it's similar here? Maybe it should dry more slowly? To keep the big cookie wet longer, I would probably try to put it in the freezer for a while. If you flooded it with RI when frozen, the RI stays wet longer (due to condensation).
Would be worth a try? @Dani Matos