Soak the cashews in the boiling water while you prepare the rest of the ingredients, about 5-10 minutes.
Add the coconut oil, honey, matcha and salt to a food processor. Drain the water from the cashews and add them in.
Purée the mixture for a few minutes, or until it is roughly chopped. Continue to run the food processor while you gradually drizzle in the oat milk.
Let the food processor run until the mixture is thick and creamy, this might take 4-5 minutes. Occasionally scrape down the sides of the food processor and add oat milk as needed.
Once the mixture is fully blended, move the butter to a jar. Eat whenever!