• Preheat your oven to 325°F (163°C) and lightly grease your donut pan. Set it aside for later.
• In a large mixing bowl, mix together the flour, sugar, cocoa powder, baking powder, cinnamon, and salt until everything is well combined. Make a little hole or "well" in the middle of the dry ingredients.
• In another bowl, whisk together the buttermilk, beaten eggs, vanilla extract, and melted butter. Then, pour this wet mixture into the well you made in the dry ingredients. Stir everything together until it's just combined. You don't want to overmix it.
• Now, get a pastry bag or a zip-top bag and fill it with the batter. If you're using a zip-top bag, just snip off one of the corners to make a hole. Pipe the batter into your prepared donut pan, filling each mold about two-thirds of the way.
• Pop the pan into the preheated oven and bake for about 8 to 10 minutes. You can check if they're done by inserting a toothpick into one of the donuts—if it comes out clean, they're ready!
• Once they're done, take the donuts out of the oven and let them cool in the pan for about 5 minutes. After that, transfer them to a wire rack to cool completely.

For the Chocolate Glaze:

• Grab a microwave-safe bowl and melt the chocolate chips in it using 30-second intervals, stirring between each interval until they're nice and smooth.
• Stir in the powdered sugar and vanilla extract until everything is well combined. Then, gradually add milk, a little at a time, until you reach your desired thickness for the glaze.
• Now, it's time to dip! Take each cooled donut and dip the tops into the chocolate glaze, then place them back on the wire rack. If you want to add some extra pizzazz, sprinkle on some colorful sprinkles while the glaze is still wet.
• Let the glaze set for a bit, and then they're ready to enjoy!