In a medium bowl, whisk together the flour, baking powder and salt; set aside.
In double boiler (or a microwave safe bowl), melt 1 cup of the chips, stirring until smooth.
In a large bowl, use an electric mixer to beat the butter and sugar until creamy. Add the melted chips and vanilla; beat in the eggs. Gradually beat in the flour mixture. Stir in the remaining chips.
Wrap the dough in plastic wrap; chill until firm.
Preheat the oven to 350°F.
Shape dough into 1 inch balls and roll each in powdered sugar. Place on ungreased cookie sheet. Bake 10 to 12 minutes, until tops appear cracked. Let stand 5 minutes on cookie sheet, then remove to a wire rack to cool completely.
Notes
If you cannot locate mint chips, just use regular semi-sweet chips and add ½ teaspoon peppermint extract.