Chocolate Peanut Butter Whoopie Pies

1 Start by turning on your oven to 350 degrees F.
2 Combine the ground flax with hot water and stir.
3 Incorporate the mixture in a large bowl with the cake mix and oil.
4 Pop the bowl into your fridge until your oven has finished preheating.
5 Once your oven is ready, scoop 10-12 cookie mounds onto your baking sheet, flatten them down slightly and bake for 10-12 minutes.
6 Let the cookies cool completely then fill with filling.
Filling
1 To make the filling - whisk together the frosting and the peanut butter.
2 Using a piping back or a ziplock bag with the tip snipped, pipe the filling onto one cookie before topping with another cookie.
3 Repeat and enjoy!