Preheat oven to 350º.
Use a pastry cutter or a fork to cut the butter, sugar, and flour together until crumbly.
Press a little more than half of the crumble mixture into the bottom of a 9×13 lined baking dish.
In a medium saucepan over low heat, mix 1 cup of the white chocolate peppermint candy and the sweetened condensed milk until smooth. Pour over the crumb crust in the dish.
Sprinkle the remaining crumble and white chocolate peppermint candy evenly over top.
Bake for 20 minutes or until edges begin to just barely brown.
Let cool completely before cutting into bars.