Preheat oven to 400ºF (200ºC)
Stir together flax seed, egg, and a small pinch of finely ground sea salt in a bowl until well combined.
Line a baking sheet with parchment paper
Pour batter into two circles on the parchment lined sheet pan. Using a spatula or the back of a large spoon, spread the batter out evenly into two 'buns.' The batter should be about 1/4" thick.
Place sheet pan in the oven on the lowest rack and bake for 10-13 minutes, or until the edges are starting to crisp, and flatbread is firm but still flexible. Remove from oven. After a few minutes, peel the flatbread bunds from the parchment paper.