Instant mashed potatoes and couscous will hydrate in cold water with a little extra time. Rolled oats you can eat dry or soaked--they're already cooked in processing (parboiled). Ramen is fried before packaging and can be eaten as a large, 300-calorie cracker.
Nothing wrong with cookies for supper, though.
My wife and I are stoveless hikers. We got that way after realizing the food that needed cooking was always the last to be eaten, and was the least appetizing stuff we carried. And clean-up was never worth it. Nor was searching fuel during resupply stops, but that's way off topic.