Preheat the oven to 350°F and prepare an 8×8 pan by greasing it and lining with greased parchment paper.
In a small saucepan over medium heat, melt the butter. Remove from heat and add the chocolate chips. Let sit for a minute and then stir with a whisk or rubber spatula until the chocolate is melted.
Add the black cocoa, almond flour, Keto Chow, and erythritol to a medium bowl and mix together. Add the butter and melted chocolate to the dry ingredients and mix.
Add the eggs and mix well. Batter will be thick.
Spread the batter smoothly in the prepared pan.
Bake for 20-25 minutes. Remove and let cool completely.
While brownies cool, melt the white chocolate in the microwave in 30-second increments, stirring in between until smooth and melted. Let cool slightly.
To make the frosting, whip the heavy cream and vanilla with an electric mixer on high speed. When it reaches stiff peaks, keep the mixer going and add the cooled melted chocolate. Whip until incorporated.
Add the chocolate cookie crumbs if using.
Add frosting to cooled brownies. If you want your frosting to be firm, refrigerate frosted brownies for at least 30 minutes.