Melt the butter and chocolate in a large glass bowl in the microwave.
Add eggs, one at a time, beating with a hand mixer at medium speed.
Gradually add the sugar, vanilla, and mint extract.
Combine flour, baking powder, and salt in a bowl–mix thoroughly. Slowly add the flour mixture into the chocolate mixture beating at low speed until well blended.
Cover and chill in the refrigerator for 2 hours.
Preheat the oven to 300 degrees.
Shape the dough into small balls then roll in powdered sugar. Place the balls on a silpat-covered baking sheet.
Bake for 16-18 minutes.
Remove from the oven and let cool on a rack. Enjoy.