Whisk together the flour, cocoa powder, baking soda and salt. Set aside.
Whisk together the melted butter, brown sugar, granulated sugar, egg, yogurt and milk.
Add the dry ingredients to the wet ingredients and fold together until combined.
Spoon or pipe the batter into the donut cavities.
Bake for 11-12 minutes.
Melt together the chocolate, butter, corn syrup and water until smooth and combined.
Once the donuts are cool, dip the tops of the donuts into the frosting.
Top the frosting with sprinkles and enjoy!