Preheat oven to 350°. Line a baking sheet with parchment paper.
In a small bowl, mix together flax and water and set aside to thicken.
In a medium mixing bowl, whisk together dry ingredients (almond flour, dark cocoa, monkfruit, coconut flour, salt and baking powder). Use a measuring cup or spatula to smash out the lumps.
Add oil and vanilla to the flax mixture. Pour wet ingredients over dry and mix. If dough is too wet, add a sprinkle of almond flour. If to crumbly, add a splash of water.
Form a ball of dough and place it on a large piece of parchment paper. Place another piece of parchment on top and roll to 1/8" thickness (or even thinner, if you like).
Cut 2" circles using a cookie-cutter (I used a plastic champagne glass). Gather the scraps and re-roll and repeat until all the dough is used up.
Place cookies on baking sheet 1/2" apart and bake about 18-20 minutes until the edges are firm and centers spring back when pressed. (watch so they don't burn!) Cool completely on a rack before frosting. *cookies will continue to crisp as they cool.
To make the cream:
Add palm shortening to a stand mixer with the paddle attachment (a hand mixer should work, too). Mix for about 15 seconds to warm/soften. Add remaining ingredients and beat until fully mixed.
Place a dollop of cream on a cookie (pipe it on with a baggie to make it easier!) and top with another cookie.
(Optional- for firmer cream, chill frosted cookies for 30 minutes) Enjoy!
To store: For best freshness (and for firm cream filling), keep refrigerated in an airtight container. Should last for 5-7 days, or about 1 month frozen. To serve: remove from fridge and place on the counter for about 20 minutes.Frosting can be made ahead and refrigerated until ready to use (bring back to room temp before using). Frosting will stay fresh in a piping bag for about 2 weeks.To make homemade powdered "sugar": blend granulated monkfruit in a small blender for about 10 seconds until powdered. Measure after blending.