In a medium bowl, whisk together flour, sugar, baking powder, baking soda, and salt. Set aside.
In a small bowl, whisk together egg, sour cream, oil, coconut milk, and vanilla. Add to flour mixture and stir until just combined.
Fill each donut cup about three fourths full.
Close the lid and bake for 3 to 5 minutes, until the tops of the donuts spring back when lightly touched. Use a wood skewer to remove donuts to a wire rack to cool.
Decorate donuts with Coconut Cream Icing and crushed toasted coconut.
Coconut Icing
Whisk together powdered sugar, coconut milk, and coconut extract.
Add more powdered sugar to thicken or more coconut milk to thin until icing reaches your desired consistency.
Notes
Tip: To fill donut cups without the mess, spoon batter into a piping bag or a plastic storage bag with a small corner cut off.