Flourless cookies form "skin" that seals in moisture I've developed a sort of recipe for flourless low-cal cookies which, so far, actually works pretty well, resulting in a soft scone-type confection, but I'm having one problem with it: upon baking, the outside of the cookie everywhere except where it contacts the bottom cooks into a sort of skin which seems to keep moisture on the interior from cooking out, so the inside of the cookie stays much more moist than I would like. The recipe actually uses cabbage which has been ground to a rice consistency and wrung out as its base. The recipe for the batter in a batch size that made three pancakes and five large scones was:


Cabbage prepared thusly, between 1/4 and 1/3 large head,
4 egg whites,
1/3 cup pumpkin puree,
1/3 cup almond milk,
Just over 1 tsp glucomannan,
2 tbsp water,
Spices and extracts,
Stevia/erythritol blend for sweetness


To bake the cookies, I put "blobs" of them(~3-4 tbsp each I think) on parchment paper which had been sprayed with cooking spray, preheated an oven to 410 F, then lowered the heat to 375 once the tray was in the oven. I left it like this for ~30 minutes before lowering the heat to 270, then after another 15 minutes lowered it to 230, and they cooked for one hour in total.
So back to my question: how can I cook out more moisture from the interior of the cookies? Would I want to skip the higher-temp. earlier stage, or maybe go for even more of a low-temp long-time method? Would puncturing them like with a fork after they're part-way cooked help? Maybe adding baking powder to the recipe? Or would reducing the liquid used in the recipe achieve this?
Unless you are salting (or sugaring) your cabbage first then draining and patting dry, baking will release more liquid than the egg whites can bind.

Recipe could use something absorbent