Place 1 cup buttercream into medium mixing bowl. Add coconut extract or syrup. Mix until ingredients are well blended, and place in regular piping bag with tip.
In a separate bowl, place 1 cup buttercream. Add blueberry syrup. Mix until well blended.
Using a tipless piping bag, cut tip a tiny bit smaller than normal, and into this, place the blueberry-buttercream mixture.
Using the coconut-buttercream mixture, pipe a ring around the outside edge of one macaron shell, leaving a space in the middle.
Fill hollow in the middle with Blueberry Crumble (about 1 teaspoon or so).
Pipe a dollop of the blueberry-buttercream on top of the crumble.
Place top on macaron; store in airtight container in the refrigerator.