For the cookies:
Preheat oven to 350 degrees and line a baking sheet with parchment paper and set aside.
Mix the six dry ingredients in a medium bowl until well blended. In a separate bowl, whisk together the melted coconut oil, liquid sweetener and vanilla extract.
Add wet ingredients to the dry and mix until well combined.
Divide the batter into 6 pieces
Place cookies several inches apart on the baking sheet and bake for 6 minutes, remove from oven and gently press cookies down with the back of a spoon, and bake for 4-6 minutes more. They should come out a bit soft as they will become harder as they cool.
For the ice cream:
Blend the bananas in a food processor until they are the consistency of soft serve ice cream. You may need to occasionally stop the processor and use a spatula the scrap the banana from the sides.
In a small bowl mix the arrowroot (or cornstarch) with the non-dairy milk and vanilla extract until thoroughly combined.
Once smooth and creamy, add in arrowroot/milk/vanilla mixture and process until well combined.
Transfer to a freezer container and freeze until solid, allowing to thaw for about 5 minutes before serving.
Allow the cooled cookies to chill in the freezer, at least 30 minutes until slightly hardened. Scoop a generous amount of ice cream onto half of the cookies and place the remaining cookies on top. Gently press down and smooth the outer edge. Place back in the freezer to set, at least 20 minutes. Serve anytime.