Preheat the oven to 350° F. Line two large cookie sheets with parchment paper. Set aside.
Mix together the peanut butter and light butter in a large mixing bowl until well combined. Add the vanilla, erythritol and oats and stir until thoroughly mixed.
In a small bowl, sift together the low GI flour and baking soda and add to the peanut butter mixture. Combine until a smooth dough forms. Sprinkle the dough with sea salt.
Shape the dough into equally shaped balls. Place about two inches apart and flatten using the tines of a fork to make any desirable pattern.
Bake for 15 minutes or until lightly browned. Cool before storing in a cookie jar or tin or serve warm.