Beat butter until smooth.
Add milk and powdered sugar. Begin with 4 C of powdered sugar and add more as needed to reach desired consistency. (Should be fairly thick but not so thick that you won’t be able to squeeze it out of a piping bag to frost.)
Add coconut extract and mix in thoroughly.
Spoon into a ziplock bag. Snip the corner of the bag and squeeze the frosting on the cupcakes.