Preheat oven to 350°F. Spray a donut tin generously with nonstick baking spray.
Sift the flour into a large bowl.
1 cup all-purpose flour
Add the baking powder, baking soda, cocoa, salt, and sugar to the flour and whisk.
½ tsp baking powder, ½ tsp baking soda, ⅓ cup unsweetened cocoa powder, ⅛ tsp kosher salt, ½ cup granulated sugar
In a medium bowl, mix the egg, yogurt, oil, and vanilla extract together.
1 large egg, ½ cup plain yogurt, ¼ cup canola oil, 1 tsp pure vanilla extract
Pour the wet ingredients into the dry and mix until the batter is just smooth. Don't over mix. If you overwork it, the gluten will develop, and you will have chewy donuts.
Transfer the batter into the donut tin using a spoon or piping bag. Fill each well only to a little more than ¾ full, as the donuts rise as they bake, and will overflow if you fill them all the way to the top.
Bake for 8-10 minutes. Test if the donuts have been baked properly by inserting a toothpick. It should come out clean. Allow the donuts to cool for 5 minutes. Then flip the pans upside down over a wire rack. Repeat as needed until all donuts have been baked.
Using a microwave-safe bowl, heat the chocolate chips, butter, milk, and vanilla extract for 30 seconds, or until melted (depends on microwave setting). Stir until smooth.
½ cup chocolate chips, 2 tbsp unsalted butter, 1 tbsp milk, ½ tsp pure vanilla extract
Generously frost the donuts with the chocolate glaze and top with sprinkles.
2 tbsp chocolate sprinkles