Beat the vegan butter and coconut oil with a mixer until creamy. Add powdered sugar, one cup at a time.
Add the creamer one tablespoon at a time until the desired spreadable consistency is reached.
Add vanilla and mix one more time to combine.
Store frosting in an airtight container in the fridge for up to 2 weeks. When you're ready to use it, allow it to come to room temperature and maybe even add another teaspoon or two of plant-based milk until the spreadable consistency returns.
Coconut oil works great in this recipe, however, if it's warm and/or humid, you should consider substituting vegetable shortening because it will hold its shape better than coconut oil, which gets soft and/or can melt in warmer temperatures.