01 - Add milk, ice cubes, vanilla ice cream, vanilla bean seeds or extract, and sugar to a blender.
02 - Blend on high speed until completely smooth and creamy, approximately 30 to 45 seconds.
03 - Taste the mixture and add more sugar if desired. Blend again briefly to incorporate.
04 - Pour into two tall glasses and top with whipped cream if using. Serve right away with straws.