Preheat the oven to 400 degrees F.
Grind the gluten free oats in a food processor until they become a fairly fine flour.
Pour the oat flour, gluten free flour, garlic powder, and salt in a bowl.
Add the melted vegan buttery spread, honey or agave, and ¼ cup water. Stir. Drizzle in more water while stirring until the dough forms a ball. The dough should not be too wet.
Place the dough on a sheet of parchment paper and cover with a sheet of waxed paper. Roll the dough out until it is quite thin, about ⅛ inch thick. Try to roll the dough as evenly as possible.*
Remove the waxed paper and place the dough on the parchment paper on the cookie sheet. Cut the dough into squares with a knife, but do not separate. Sprinkle a little water on top and smooth it over the dough.
Sprinkle sea salt flakes on top.
Bake at 400 degrees F for 13-16 minutes, until golden brown and crisp, rotating the sheet once during the baking time.
Let cool before breaking into squares.