Preheat the oven to 350 degrees F (180 degrees C). Line an 8×8″ baking dish with parchment paper.
Tapioca Starch (1/3 cup)
Unsweetened Cocoa Powder (1/3 cup)
in a medium bowl until no lumps remain.
Dark Chocolate (1 1/2 cups)
Coconut Oil (1/3 cup)
in a small saucepan over low, stirring, until melted and smooth. DO NOT bring to a boil!
Using an electric mixer on medium-high speed, beat
Large Eggs (4)
Granulated Monk Fruit Sugar (2/3 cup)
Coconut Sugar (1/2 cup)
in a large bowl until light and smooth, about 3–4 minutes.
Kosher Salt (1 tsp)
Vanilla Extract (1/2 Tbsp)
to combine, then beat in chocolate mixture, scraping down sides as needed, until incorporated.
Beat in tapioca flour mixture, then increase speed to medium-high and beat until mixture is thick and holds its shape, about 30 seconds.
Pour into a parchment-lined baking pan and bake until a cake tester or toothpick comes out clean, approximately 20-25 minutes.
Once ready, let cool and serve.