Preheat oven to 350 degrees F (176 C) and place macadamia nuts on a baking sheet.
Bake for 8-10 minutes or until the macadamias have a bit of golden color and become fragrant. Remove from oven and let cool for a few minutes.
Add nuts to a food processor and blend into a meal. Remove and set aside.
Add coconut flake to the processor and blend until creamy and smooth. This will take anywhere from 5-10 minutes depending on the strength/blade of your food processor. Scrape down sides as needed.
As soon as you have your coconut butter, add macadamia nut meal and vanilla and blend again until smooth.
Add powdered sugar 1 Tbsp at a time until you reach desired sweetness. I found that 5-6 was perfect for me, plus helped it thicken up a bit (amount as original recipe is written).
At this point it's perfect for adding to a squeeze bottle or piping bag and piping onto your baked good. Otherwise, you can refrigerate it to make it thicker. Will keep stored in the refrigerator for up to a month. Recipe (as originally written) makes enough to frost at least 3-4 dozen cookies + leftovers.
*Nutrition information reflects 1 of about 50 servings. This is just an estimation. *If you can't find or don't like macadamia nuts, sub a similar nut such as cashews. *Make chocolate frosting by adding ~ 1/2 cup melted bittersweet chocolate.