Preheat the oven to 350 F/177 C.
Crush the cinnamon toast crunch cereal into a small bowl and add the milk. Stir to combine, then set aside while you prep the batter.
½ cup cinnamon toast crunch cereal, ½ cup + 2 tablespoon 2% milk
In a medium bowl, add the melted butter, sugar, and brown sugar and whisk to combine.
2 tablespoon unsalted butter, melted, ¼ cup granulated sugar, ¼ cup brown sugar
Add in the egg and whisk until smooth and combined.
1 large egg, room temperature
Add the milk and soaked cereal to the bowl and whisk to combine.
Add the flour, cocoa powder, salt, baking powder, and baking soda to the bowl and whisk until JUST combined. Do not over mix!
⅔ cup all-purpose flour, ¼ cup dutch process cocoa powder, 1 teaspoon baking powder, ¼ teaspoon kosher salt, ¼ teaspoon baking soda
Spoon the batter into the donut pan until each spot is half full.
Bake the donuts on the middle rack for 7-8 minutes, or until the tops spring back when touched. Then let the pan cool on a wire rack for a few minutes.
Meanwhile make the glaze. Combine the powdered sugar, milk, vanilla, and cocoa powder in a bowl and whisk until smooth.
2 cups powdered sugar, ¼ cup cocoa powder, ½ teaspoon vanilla extract, 3-4 tablespoon 2% milk
When the donuts are cool, gently remove them from the pan. Dip them in the bowl of the glaze then sprinkle them with extra cinnamon toast crunch pieces.
cinnamon toast crunch pieces, for topping