These cake mix donuts are really simple to make and don’t require any deep frying in oil. They taste similar to cupcakes, though the added sour cream gives them some moisture and a denser texture.
In a large mixing bowl, whisk together the dry cake mix, oil, milk, eggs, and sour cream until fully combined.
Transfer batter to a piping bag.
Spray a donut pan with non-stick baking spray (the kind with flour works best). Pipe a ring of batter into each donut cavity. Do not fill each cavity more than 1⁄2 full.
Bake donuts for 10 minutes, until puffed and just beginning to turn golden.
Remove from oven and turn out onto a cooling rack. Continue baking batches of donuts.
Prepare the glaze by whisking together powdered sugar, milk, and cocoa powder, if using.
Dip the smoothest side of the donut into the glaze, allowing some excess to drip off and then place on a cooling rack or platter. Decorate immediately with sprinkles before the glaze sets.
Notes
If you don't have a piping bag, simply add the batter to a large ziptop bag and snip off the corner.
The donuts rise quite a bit in the oven. If the cavities are filled too full, they will spill over the tops and make an odd shape. Keep the batter under the halfway point of the cavity so that when they rise, they make an equally cute donut shape on both halves.
Allow the donuts to cool slightly before dipping them in the glaze. If the glaze is too thick, it may be difficult to dip the donut in and lift it out without it breaking. If necessary, you can also drizzle the glaze over the tops of the donuts.
The glaze will set dry to the touch after 5-10 minutes. Be sure to add the sprinkles immediately after dipping/glazing so that they stick.
Store donuts in a single layer in an airtight container kept at room temperature for 2-3 days.