Preheat oven to 350°F. Line a baking sheet with parchment paper.
In a medium bowl, whisk together dry ingredients: almond flour, dark cocoa, monkfruit, coconut flour, salt, and baking powder. Smash out lumps with a measuring cup or spatula.
Add oil and vanilla to the egg mixture. Pour wet ingredients over dry ingredients and mix. If too wet, add more almond flour. If too dry, add a splash of water.
Form dough into a ball. Roll between two sheets of parchment paper to ⅛" thickness (or thinner).
Cut into 2" circles with a cookie cutter (or champagne glass). Re-roll scraps and repeat.
Bake on a parchment-lined sheet, ½" apart, for 5-10 minutes. Cool completely on a rack. Cookies will crisp as they cool.
Add butter to a stand mixer with paddle (or use hand mixer). Mix for 15 seconds to soften.
Add remaining ingredients and beat until fully combined.
Place a dollop of cream on a cookie, top with another cookie.
Optional: chill frosted cookies for 30 minutes for firmer filling.
