Place the butter into a large mixing bowl or the bowl of a stand mixer fitted with a paddle attachment. Beat for a few minutes, until light and fluffy.

Add the powdered sugar, maple extract, vanilla extract, maple syrup, and 1 teaspoon of milk and beat again, until light and fluffy. If necessary, mix in more milk, approximately 1/2 teaspoon at a time, until the desired consistency is reached. Scrape the sides as necessary.

To remove air bubbles, use a rubber scraper to stir the buttercream a bit and press it up against the sides of the bowl.