In a medium-size mixing bowl, beat cold butter until light.
Add sugars until creamed.
Gradually add flour and peppermint extract. Continue to mix until dough comes
Add 1/2 cup of crushed candy and press into a lightly greased cookie sheet. Poke
holes all over the flattened dough using a fork.
Chill for 20 minutes and then place into a preheated 325 degree F oven for 20
to 25 minutes. Shortbread should be lightly browned.
While they are still warm, cut cookies into squares with a straight edge and
allow to cool.
Using a double boiler, bring to a low simmer and melt white chocolate slowly,
stirring often. White chocolate can only be melted very slowly in a glass bowl in
a microwave at 50% power for a minute or two only.
With a whisk or fork, drizzle warm white chocolate over cookies and sprinkle
with crushed peppermint.