Peel the avocados and remove the pits. Chop them roughly into large chunks and add them to the food processor along with the cocoa powder and maple syrup.
Pulse until smooth, stopping to wipe down the bowl as needed. Taste a bit of the frosting and add 2 to 4 tablespoons of additional syrup if necessary.
Add this frosting over a baked and cooled cake for a healthy, low sugar frosting.