For the Donuts: Preheat the oven to 350 degrees F. Coat a standard-sized donut pan with nonstick cooking spray. Set aside.
In a medium bowl, whisk flour, baking powder and baking soda. In a separate medium bowl, whisk egg, brown sugar, milk, yogurt, butter and vanilla until smooth. Stir wet ingredients into dry ingredients, just until combined (don’t over-mix). The batter will be very thick.
Spoon batter into donut cavities* and bake for 8-10 minutes, until donuts are golden and spring back to the touch. Allow donuts to slightly cool before glazing.
For the Chocolate Glaze: In a medium bowl, combine chocolate chips, butter, corn syrup and water. Microwave in 20-second increments, stirring after each time, until completely melted and smooth. Dip donut tops into the chocolate glaze then coat with sprinkles.