Prepare cupcakes according to package and add in the vanilla pudding mix. Bake according to package directions. I use dark colored pans and bake at 325 degrees.
Cool cupcakes completely.
Use a cupcakes corer to remove the center of the cupcake.
Add 4 drops Blueberry flavor to two cups of frosting.
Cut up 1/4 cup blueberries and mix them with 1/2 cup of the frosting and fill hte cupcakes with it.