Add the coconut oil, powdered sugar, and vanilla powder to a mixing bowl. I recommend a stand mixer, as the coconut oil takes a long time to cream. Cream the coconut oil and sugar and vanilla until creamy. (This can take several minutes) Add the rice milk slowly while stirring. Continue beating frosting until all coconut oil lumps are gone- it’s worth it – this is a delicious frosting!
Vanilla powder is made of dextrose and vanilla extract. If you can’t find vanilla powder, you can use liquid extract (1-2 tsp), but the result is not as nice. You will need to lower the amount of milk or increase powdered sugar to compensate.