Place butter and 1 cup powdered sugar in mixing bowl and blend until smooth.  Add remaining powdered sugar, milk, and extract and beat for a full minute until light and fluffy.  Frosting will be thick, add additional milk a TEENY bit at a time (like 1/2 teaspoon) if you need to thin it out just a bit.  I suggest keeping it on the thick side.  Add more extract if desired, I like about 1 1/2 teaspoons.

Gently break graham crackers into segments.  It helps to use a sharp knife to score first if they are crumbly.

Spread frosting on crackers and sandwich with another cracker.  Place finished sandwiches in freezer.

If desired.  Melt chocolate chips and oil in the microwave in 30 second intervals until smooth.  Drizzle over cookies and return to freezer.

You may alternately eat unfrozen or simply dunk crackers in frosting like a dip :)