dark chocolate (at least 70 percent cacao), chopped (use a refined sugar–free version like this one)
raw cacao powder (such as this one)
mint-flavored dark chocolate, finely chopped, divided (use a refined sugar–free chocolate, such as this one)
Preheat oven to 350 degrees F and line an 8-inch square baking dish with parchment. In a large bowl set over a pot of simmering water, melt butter and dark chocolate, stirring occasionally, until smooth. Remove from heat and set aside to cool.
In a small bowl, combine cacao, arrowroot, collagen, and salt; stir to mix well. In a cup, rub coconut sugar and mint together with your fingers or a fork to draw oils out of mint. When chocolate mixture has cooled, whisk in eggs, coconut sugar-mint mixture, and vanilla. Fold in cacao mixture, then half of chopped mint chocolate. Transfer batter to baking dish, spreading top evenly, and sprinkle with remaining chopped chocolate.
Bake until just set and a toothpick inserted in center comes out with moist crumbs attached, about 24 to 27 minutes. Let cool in pan on a wire rack. Cut into bars, or cover and refrigerate to serve later.
Store leftovers in an airtight container in the refrigerator for up to one week.
Photography and prop styling by Julia Gartland. Food styling by Samantha Seneviratne.