For the Filling:
Bring coconut and milk to a simmer over medium heat.
Sift together the sugar and cornstarch then add to milk mixture.
Stir the filling mixture continuously until it thickens; store uncovered in the refrigerator until ready to use.
For the Frosting:
Combine everything but the sugar in a microwave safe bowl. Heat in the microwave for 40 seconds. Stir
Return to the microwave for 20 more seconds.
Remove the bowl (carefully) from the microwave and stir in sugar. Combine well, adding more sugar to reach your desired consistency.
Stir in the fridge until you're ready to use.