Preheat mini donut maker while you prepare your batter.
Combine the cake mix, egg, oil & water in a large bowl & whisk well until mostly smooth.
Once your donut maker is hot & ready, spoon about 2 tbsp of batter into each donut well.
Close the lid & cook approx 5-6 minutes.
Remove & place on wire rack to cool. Continue with remaining batter.
Once donuts are cooked & cooled combine glaze ingredients in small bowl & whisk until fully combined.
Dip each donut into the glaze to coat the top & return to the wire rack.
Immediately sprinkle with Oreo crumbles & chocolate jimmies before your glaze hardens.
Allow them to set before serving.