In a microwave safe bowl melt butter and chocolate, stirring every thirty seconds, until all is melted.
Stir in sugar.
Blend in eggs, vanilla, mint extract and bourbon.
Use a small cookie scoop or ice cream scoop, scoop batter into a mini muffin pan that's been well greased.
Bake at 350 degrees for 12-14 minutes.
Insert toothpick into the center of the brownies to check for doneness.
More time may be needed by a couple of minutes.