In medium saucepan melt butter for 6-7 minutes stirring continuously over medium heat until a slight brown tint appears.
Add the brown sugar and stir until combined. Remove from heat and cool completely.
Prehaet oven to 350 degrees. Cut a piece of parchment paper that will line an 8x8 square pan.
In a small mixing bowl add flour, xanthan, baking powder, cinnamon and salt. Whisk together and set aside.
In small bowl add egg replacer with warm water and let thicken for one minute.
In bowl of stand mixer add brown butter mixture, egg replacer, and vanilla. Mix for 1-2 minutes.
Add flour and apples. Use a spatula to continue mixing as you slowly add the cold water. Batter will be a little sticky.
Let dough fall onto the center of the square pan and begin pressing it out from the center to the edges until it is evenly spread out.
Bake for 25 minutes.
Let cool for at least an hour before cutting
Serve and enjoy!