Preheat the oven to 350ºF and line a baking sheet with parchment paper.
In a large bowl, combine the almond butter, coconut sugar, egg, baking soda, and salt. Stir well to create a thick, uniform batter.
Use a tablespoon to drop the dough onto the lined baking sheet, keeping the cookies about 2 inches apart. Use a fork to flatten each mound of dough, and sprinkle the tops with coarse sea salt, if desired.
Bake the cookies until lightly golden, about 12 to 13 minutes. For a crispier cookie, you can bake them for 15-20 minutes, just watch to make sure that they don't get too dark or burn.
Allow the cookies to cool on the pan completely before serving. They are very fragile when warm, but they firm up when cool. You can store the cookies in an airtight container on the counter for a couple days, but store them in the fridge or freezer for a longer shelf life. (They are extra-crunchy if you serve them frozen.)