Crispy Lembas Bread Recipe
I don't remember what the Lembas are supposed to be like in the original text, but whatever Tolkien intended them to be, the recipe is not for a bread-like item in the sense modern US Americans understand it. It is more comparable to waffles. 

This is why it got wrong when you tried to treat it like bread. It is a batter, not a dough. The slow indirect heat of an oven is wrong for it, and it is not supposed to be able to hold its shape as a loaf. If you don't have a pizzelle iron, use a waffle iron for making them. If you don't have a waffle iron either, use a griddle or a hot pan and form and bake the lembas like pancakes, turning them during the process to get both sides baked. 

Although I am saying "pancake" here, it refers to the cooking process, not to the final texture. If the chef who made the recipe knew what he was doing, the result can be crispy and flaky, similar to a dried tortilla. It will indeed be calorie-dense and durable, just like the fictional lemba. 

As I don't think Tolkien gives anything closely usable as a culinary recipe, I guess that the chef just baked anything with these two qualities and called it "lemba". You can probably take any other kind of durable bread and use it as your recipe if you don't like this one. Knaeckebrod is probably a good starting point, considering that it has similar properties, and it is probably appropriate, seeing how much Tolkien was influenced by Nordic mythology.