Preheat the oven to 375°F. Line 2 baking sheets with parchment paper.
To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, add the butter and brown sugar. Mix on low until combined.
Add in the yogurt, heavy whipping cream, flour, cocoa powder, baking powder, salt, and vanilla bean in that order. Mix on low until combined into a cookie dough.
Using your hands, form the dough into 12 balls and flatten them slightly so they are about 2-inches in diameter, and place on the prepared baking sheets. You’ll have 6 cookies per sheet, space them evenly apart.
Bake for 14 to 16 minutes or until the edges look dry. Allow the cookies to cool completely on the baking sheets.
To make the frosting: Add the chocolate and cream to a heatproof mixing bowl. Microwave for 30 second intervals, stirring between each one to prevent burning, until the chocolate is completely melted. (You can also do this by melting the chocolate in a double boiler and slowly adding in the cream).
Using a butter knife, frost the cookies and add the chocolate coated candy sprinkles on top.
Store in an airtight container in the fridge for up to 5 days.